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The metapleural gland is a unique feature of the ant phenotype, but diversity in its anatomy and function across the ants is not well documented or understood. We studied the morphology of the metapleural gland in 20 mainly Oriental Strumigenys species using histology, scanning and transmission electron microscopy, and micro-CT. The gland is formed by a cluster of class-3 cells, their secretion is transported through a bundle of ducts into the sclerotized atrium and is guided along a series of parallel cuticular ridges towards the atrial opening. Among the examined species, queens have more gland cells than conspecific workers, while the examined males do not have the gland. The social parasite S. mutica has the most developed metapleural gland. In addition, we describe a novel class-1 atrial cone gland which is associated with the metapleural gland. The epithelium of this cone gland forms an invagination into the ventral atrium of the metapleural gland. The cuticular cone may be lacking in some Afrotropical and Neotropical species, although these may still contain the epithelial gland. The functional and evolutionary drivers of morphological variation in the exocrine system across species form interesting questions for future work., Competing Interests: Declaration of Competing Interest We herewith confirm that there exists no conflict of interest among the authors of our manuscript “Morphology of the metapleural gland and its associated novel atrial cone gland in Strumigenys ants”., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The insect cuticle is multifunctional and often includes projections used for support, communication or protection. Ants in the genus Strumigenys exhibit a peculiar honeycomb-like spongiform tissue that covers their petiole, postpetiole and sometimes also the posterior mesosoma and anterior part of the first gastral segment. The tissue is abundantly developed in workers and queens, and much reduced in males. We found this spongiform tissue is associated with a novel exocrine gland that is made up by class-3 secretory cells that are clustered underneath the major pillars of the cuticular extensions, their associated narrow ducts enter these extensions and open at the surface through small pores. The chemical nature and function of the secretion are still unknown. The honeycomb texture may act in the storage and dispersion of the glandular secretions. In addition to the spongiform tissue gland, the posterior region of the petiole and postpetiole also contain intersegmental petiole and postpetiole glands, of which the ducts open through the intersegmental membrane that forms the connection with the next segment. Future work aimed at identifying the chemicals secreted by these glands will shed light onto the function of these unusual structures., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Alien species may pose substantial impacts on biodiversity around the globe through international trade and travel. A niche shift hypothesis was proposed to explain the adaptive change of alien or invasive species in new habitats. However, whether niche shifts occur in alien species likely depends on both characteristics inherent to the species itself and its original distribution. Here we identified a newly exotic trap-jaw ant ( Odontomachus troglodytes ) in Taiwan by morphological and phylogenetic analyses. The possible distribution range and the niche shift pattern were evaluated using ecological niche modelling. The results indicated that exotic O. troglodytes in the newly distributed area displayed a significant niche shift with low niche overlap and high niche expansion. This study reveals a long-distance invasive event from central Africa to Southeast Asia (more than 10,000 km) and predicts the potential distribution range of this new alien species in Taiwan., Competing Interests: The authors declare there are no competing interests., (©2023 Lin et al.)

Research into geographical invasions of red imported fire ants (RIFAs) by anthropogenic disturbances has received much attention. However, little is known about how land-use change and the characteristics of roads with different land-use types are associated with the risk of RIFA successful invasion or remaining at the highest level of invasion (RIFA SIRH). Furthermore, it was often assumed in prior studies that the risk of RIFA SIRH had a linear association with the independent variables. However, a linear relationship may not reflect the actual circumstances. In this study, we applied linear and nonlinear approaches to assess how land-use types, distance from the nearest road, different land-use types, and spatial factors affect the risk of RIFA SIRH. The results showed that agricultural land, land for transportation usage, and areas that had undergone land-use change from 2014 to 2017 had greater odds of RIFA invasion than natural land cover. We also identified land for transportation usage and the area of land-use change from 2014 to 2017, had more than 60% of RIFA SIRH within 350 m and 150 m from the nearest road. This study provided important insights into RIFA invasions in an isolated island and the areas of control strategies implemented., (© 2022. The Author(s).)

The morphology of the infrabuccal pocket has been studied with light and electron microscopy (SEM, TEM) in 19 species of Strumigenys ants. The structural organization is similar in workers, queens and males, and supports the involvement of the pocket in the filtration of food particles before they can enter the digestive tract. A carpet of posteriorly oriented bristle hairs on the hypopharynx first guide ingested food into the pocket, where large solid particles are compacted into a pellet that will be regurgitated. The remaining products enter the digestive tract through a filtering wall of parallel hair combs lining the pharynx interior that are directed against the food flow. This mechanical filtering allows only liquids and sufficiently small food particles to enter the digestive system. The wall of the infrabuccal pocket is differentiated into a conspicuous glandular epithelium, of which the ultrastructural characteristics can be understood as an adaptation against the frequent shape changes of the pocket. The gland elaborates a non-proteinaceous secretion, although its functional significance still remains unknown., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The red imported fire ant, Solenopsis invicta Buren, was first discovered in Japan in 2017. As this ant remains at the early invasion stage, efforts in establishing a rapid-response framework, such as evaluating available control methods, are urgently needed. Despite the presence of numerous household insecticides against invasive/household pest ants in Japan, the effects of these products on fire ants remain poorly understood. This study assessed the efficacy of two bait products designed to target common household ant pests in Japan on S. invicta through under laboratory and field conditions in Taiwan. The two baits are Arino-su-korori (AK), a granule-formulated bait product with hydramethylnon as an active ingredient (A.I.), and Hyper Arino-su-korori (HAK), a paste-formulated bait with fipronil as A.I., respectively. We showed that both AK and HAK resulted in more than 99% mortalities of fire ant within 8 wk under laboratory conditions and significantly reduce fire ants' foraging activities in the field. AK generally performed slightly better than HAK in terms of the time required to achieve total laboratory colony elimination and also long-term suppression of field fire ants. Such differences most likely are attributable to the active ingredient's mode of action and/or formulation and their interactions with fire ant biology. This study demonstrates the feasibility of the two bait products in effectively controlling laboratory and field fire ants, thus representing a promising candidate pest management tool to cope with ongoing/future fire ant invasions in Japan., (© The Author(s) 2022. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Animal hosts infected and killed by parasitoid fungi become nutrient-rich cadavers for saprophytes. Bacteria adapted to colonization of parasitoid fungi can be selected and can predominate in the cadavers, actions that consequently impact the fitness of the parasitoid fungi. In Taiwan, the zombie fungus, Ophiocordyceps unilateralis sensu lato (Clavicipitaceae: Hypocreales), was found to parasitize eight ant species, with preference for a principal host, Polyrhachis moesta. In this study, ant cadavers grew a fungal stroma that was predominated by Bacillus cereus/thuringiensis. The bacterial diversity in the principal ant host was found to be lower than the bacterial diversity in alternative hosts, a situation that might enhance the impact of B. cereus/thuringiensis on the sympatric fungus. The B. cereus/thuringiensis isolates from fungal stroma displayed higher resistance to a specific naphthoquinone (plumbagin) than sympatric bacteria from the environment. Naphthoquinones are known to be produced by O. unilateralis s. l., and hence the resistance displayed by B. cereus/thuringiensis isolates to these compounds suggests an advantage to B. cereus/thuringiensis to grow in the ant cadaver. Bacteria proliferating in the ant cadaver inevitably compete for resources with the fungus. However, the B. cereus/thuringiensis isolates displayed in vitro capabilities of hemolysis, production of hydrolytic enzymes, and antagonistic effects to co-cultured nematodes and entomopathogenic fungi. Thus, co-infection with B. cereus/thuringiensis offers potential benefits to the zombie fungus in killing the host under favorable conditions for reproduction, digesting the host tissue, and protecting the cadaver from being taken over by other consumers. With these potential benefits, the synergistic effect of B. cereus/thuringiensis on O. unilateralis infection is noteworthy given the competitive relationship of these two organisms sharing the same resource., (© 2021. The Author(s).)

We describe a novel ventral scape gland in all 19 species of the genus Strumigenys that we examined, confirming the postulated existence of this gland by Bolton (1999). The gland occurs in workers and queens; it belongs to 'class-1' and is formed by a layer of epithelial secretory cells that line the ventrodistal tegumental cuticle of the antennal scape. The gland is characterized by its bowl-shape, by the ultrastructural characteristics of microvillar arrangement and by the presence of nerves in between the epithelial cells. These features make this gland structurally very similar to 3 other epithelial glands that occur exclusively in Strumigenys. Besides the epithelial ventral scape gland, also scattered class-3 glandular cells are found. The function of both glands in the scape remains unclear, although a role in prey attraction cannot be excluded., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The yellow crazy ant, Anoplolepis gracilipes was first reported in Kenting National Park, Taiwan, in the 2000s, raising the concern of this invasive ant's potential effects on the native land crab populations. We investigated the distribution and abundance of A. gracilipes and its adverse effect on the land crab populations at four land crab hotspots within the park. Our survey results indicated that A. gracilipes was widespread and abundant at three of the study sites (Hsiangchiaowan, Shadao, and Natural Spring), while the distribution was much more confined at the fourth site (Houwan). Land crab populations experienced a notable decline at all the study sites except Houwan, indicating an inverse relationship between the population of land crabs and distribution/abundance of A. gracilipes. Combining the results of visual observations, the decline of land crab populations can be attributed, at least partially, to direct attacks by A. gracilipes on land crabs in their natural habitat and during the breeding migration season. Generalized additive model showed that worker abundance of this ant is associated with human disturbance levels, suggesting that anthropogenic disturbance may have contributed to the decline in land crab populations via promoting the abundance of A. gracilipes.

The first report of the red imported fire ant (RIFA), Solenopsis invicta Buren, in Taiwan was in the city of Taoyuan in 2003. The government has made great efforts to bring RIFA-infested areas under control. RIFA has gradually spread outward since its discovery, but it is still confined in northern Taiwan, in part due to the control efforts. RIFA is well established in densely populated environments (i.e., urban areas), causing damage to public utilities and significantly affects the inhabitants of Taiwan. Out of 10,127 human encounters with RIFA reported by the Plant Pest Information Management System in the Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture, Executive Yuan, 3819 (37.71%) persons were stung, with 834 (21.8%) persons exhibiting wheal-and-flare reaction (swelling and redness of the skin). Among the victims, 288 (7.5%) sought medical care, and about 21 (0.6%) developed severe cellulitis and urticaria. Unexpectedly, 2.8% (106) of the victims exhibited anaphylactic shock, which was higher than previously reported cases (1%). The high anaphylactic shock percentage was probably because most victims were elderly farmers or because Asian people have higher sensitivity to the RIFA sting. RIFA is well adapted to the environmental conditions in Taiwan, which makes it extremely difficult (if not impossible) to eradicate. The management of RIFA in the future should focus on lowering the speed of spread to mitigate possible dangers to the inhabitants. Six major challenges of RIFA management in Taiwan are also discussed.

Workers, queens and males of all examined Discothyrea species of the 'sauteri group', that have laterally expanded frontal lobes and well-developed antennal scrobes, are characterized by two hairy areas on the outer surface of their procoxae. Histological and ultrastructural examination of Discothyrea sauterirevealed that each of these areas is associated with a novel exocrine gland: the proximal procoxal gland is formed by a cluster of 15 round secretory cells of 34 μm with numerous mitochondria, smooth endoplasmic reticulum and Golgi apparatus.Their ducts have a diameter of 0.5-1 μm.The distal procoxal gland contains 50 secretory cells of 22 μm with numerous vacuoles and lamellar inclusions, and narrow ducts with a diameter of only 0.15-0.2 μm.The differences in ultrastructural appearance and duct diameter indicate that both glands produce a different but probably pheromonal secretion. The function of these novel procoxal glands could not yet be determined, although observation of D.sauteri workers and queens shows that they make frequent and peculiar leg movements, in which the foreleg basitarsus rubs over the coxal hairy areas. The foreleg basitarsus then rubs the ipsilateral hindleg basitarsus and antenna. As a last step of the sequence, the hindleg basitarsus strokes the gaster.In addition to the occurrence of these novel procoxal glands, histological examination of D. sauteri also revealed the presence of yet another novel but smaller procoxal base gland. Ants of the 'testacea group', that have less developed frontal lobes and no antennal scrobes, do not have procoxal hairy areas, although a distinct sculpturation with small pores may occur in the corresponding areas. The related Proceratium japonicum, that has a similar lifestyle as Discothyrea, does not have any of the procoxal glands and does not display the peculiar leg movements as reported for D. sauteri., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Pangolins are myrmecophagous mammals whose biology and ecology remain poorly studied. Termite mandibles and ant head capsules are the two primary remains found in pangolin feces. Determining the retention time of insect cuticles is important for understanding the digestive physiology of pangolins, while determining the recovery rate of termites and ants in feces is required to estimate the number of these prey items that are consumed by pangolins. In this study, the authors conducted feeding trials with captive Chinese pangolins (Manis pentadactyla). Sixty grams of the fungus-growing termite Odontotermes formosanus (18,816 individuals) and 15-20 g of the yellow crazy ant Anoplolepis gracilipes (14,400-19,200 individuals) were fed to each pangolin. After feeding, pangolin feces were collected daily for 1 week. The authors also assessed the accuracy of using chromium (III) oxide powder (Cr 2 O 3 ) as a proxy for determining gut passage time, as has been done in previous studies. The results showed that remaining termite mandibles and ant head capsules in feces peaked at 66 and 90 hr after feeding and their recovery rates were 0.35 ± 0.10 and 0.65 ± 0.04, respectively. In both feeding trials, the retention time of Cr 2 O 3 was much shorter than that of the termite mandibles and ant head capsules, indicating that Cr 2 O 3 is not an appropriate indicator for estimating food retention time of myrmecophagous animals. Our results revealed that the ant head capsules were preserved better in feces compared with the termite mandibles, suggesting that termites may be considerably underestimated in the feces of wild pangolins., (© 2020 Wiley Periodicals, Inc.)

It is essential for the survival and reproduction of parasitoids to adapt to the fluctuating host resources. Phenotypic plasticity may enable a parasitoid species to successfully achieve its control over a range of host species to maximize fitness in different hosts that may each require dissimilar, possibly conflicting, specific adaptations. However, there is limited information on how the fitness effects of host switching partition into costs due to the novelty of host species, where unfamiliarity with host physiological and morphological changes and its anti-parasite defenses reduces parasitoid growth, survivorship and/or reproductive success. In this study, the parasitoid fungus Ophiocordyceps unilateralis sensu lato was found to sympatrically infect a principal host ant species and other alternative sympatric hosts in the forest of central Taiwan. We herein report that the occurrence of ant infections by O. unilateralis s.l. shows spatial and temporal variation patterns on different host species. Results showed that the height from the ground to the leaf where the infected ants grip on, perithecia-forming ability, and growth rate of the stroma of the parasitoid fungus were dissimilar on different host species. These host range expansions not only related the fitness of O. unilateralis s.l. but also influenced the expression of extended phenotypic traits. Our findings revealed that a generalist parasitoid fungus suffered an evolutionary tradeoff between host breadth expansion and host-use efficiency.

Ponera is a widespread genus of litter and soil ants. The highest diversity of the genus is found in Asia, with Taiwan and Japan being two of the most species-rich regions. Here, we systematically review the taxonomy of the 16 Taiwanese and Japanese Ponera species, two of which are new species from Taiwan: Ponera terayamai sp. n. and P. wui sp. n. A new key for Ponera species of East Asia is presented.

The Taiwanese species of the ant genus Technomyrmex are revised with recently collected material. Five species are recognised, three in the T. albipes species group and two in the T. bicolor species group, including one new species, T. formosensis sp. nov., and two newly recorded species. The occurrence of T. albipes, previous records of which were based on misidentifications, is confirmed for the first time in Taiwan. The structure of genitalia is compared between winged and wingless males of T. brunneus.

The Dolichoderus thoracicus (Smith) has seriously infested urban, village, and agricultural environments in Taiwan. To develop optimal bait for the effective control of D. thoracicus, we investigated the feeding preferences of this ant at different sugar and amino acid concentrations in a laboratory setting. The number of feeding workers was significantly higher for 20% sucrose compared with that for other sugars at 10% and 20% concentrations. Furthermore, among all tested concentrations of monosodium glutamate (MSG; 1%, 3%, 5%, and 10%), the highest number of ants were attracted by 1% MSG with 20% sucrose. The consumption of each bait solution was also measured, and the results were similar to those for ant number. Regarding toxicants, the toxicity and repellency of 3% boric acid and borax bait were evaluated individually. Both 3% boric acid and borax demonstrated no repellency against D. thoracicus workers. The LT50 of the 3% boric acid bait was 4.87 d, whereas that of 3% borax bait was only 1.56 d. Thus, 3% boric acid showed further delayed action, facilitating workers spreading the toxicant to their nestmates through trophallaxis. In combination with our unique bait station, we propose an optimal bait formulation comprising 20% sucrose, 1% MSG, and 3% boric acid as a promising candidate for controlling D. thoracicus., (© The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The collective egress of social insects is important in dangerous situations such as natural disasters or enemy attacks. Some studies have described the phenomenon of symmetry breaking in ants, with two exits induced by a repellent. However, whether symmetry breaking occurs under high temperature conditions, which are a common abiotic stress, remains unknown. In our study, we deposited a group of Polyrhachis dives ants on a heated platform and counted the number of escaping ants with two identical exits. We discovered that ants asymmetrically escaped through two exits when the temperature of the heated platform was >32.75°C. The degree of asymmetry increased linearly with the temperature of the platform. Furthermore, the higher the temperature of heated platform was, the more ants escaped from the heated platform. However, the number of escaping ants decreased for 3 min when the temperature was higher than the critical thermal limit (39.46°C), which is the threshold for ants to endure high temperature without a loss of performance. Moreover, the ants tended to form small groups to escape from the thermal stress. A preparatory formation of ant grouping was observed before they reached the exit, indicating that the ants actively clustered rather than accidentally gathered at the exits to escape. We suggest that a combination of individual and grouping ants may help to optimize the likelihood of survival during evacuation.

Background: Centromeres are essential for accurate chromosome segregation, yet sequence conservation is low even among closely related species. Centromere drive predicts rapid turnover because some centromeric sequences may compete better than others during female meiosis. In addition to sequence composition, longer centromeres may have a transmission advantage., Results: We report the first observations of extremely long centromeres, covering on average 34 % of the chromosomes, in the red imported fire ant Solenopsis invicta. By comparison, cytological examination of Solenopsis geminata revealed typical small centromeric constrictions. Bioinformatics and molecular analyses identified CenSol, the major centromeric satellite DNA repeat. We found that CenSol sequences are very similar between the two species but the CenSol copy number in S. invicta is much greater than that in S. geminata. In addition, centromere expansion in S. invicta is not correlated with the duplication of CenH3. Comparative analyses revealed that several closely related fire ant species also possess long centromeres., Conclusions: Our results are consistent with a model of simple runaway centromere expansion due to centromere drive. We suggest expanded centromeres may be more prevalent in hymenopteran insects, which use haplodiploid sex determination, than previously considered.

Among social Hymenoptera, only some ant genera have more than one morphological kind of non-reproductive adults. Individuals that are bigger than ordinary workers can function for defence and/or food storage. In Crematogaster (Orthocrema) smithi from Arizona, a third caste exists in addition to winged queens and workers; it is intermediate in size, weight and morphology, and individuals lay many unfertilized eggs that are mostly eaten by larvae (Heinze et al., 1995, 1999). We studied another three species belonging to the subgenus Orthocrema: Crematogaster pygmaea from Brazil, Crematogaster biroi and Crematogaster schimmeri from Taiwan. Using scanning electron microscopy and ovarian dissections, we show that 'intermediates' are a patchwork of queen-like and worker-like traits, just as in C. smithi; importantly the combinations differ across species. 'Intermediates' are numerically few in the colonies, and in C. pygmaea they are produced seasonally. Using histology we confirmed the lack of a spermatheca, thus they are not ergatoid queens. Based on the similarity of their mosaic phenotypes with those in other ant lineages, we suggest that Orthocrema 'intermediates' are a soldier caste with a specialized trophic function. This soldier caste has been reported in other Orthocrema species from Madagascar, Guinea and Costa Rica, suggesting that it is widespread in this subgenus., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

In this investigation, detection dogs are trained and used in identifying red imported fire ants, Solenopsis invicta Buren, and their nests. The methodology could assist in reducing the frequency and scope of chemical treatments for red imported fire ant management and thus reduce labor costs and chemical use as well as improve control and quarantine efficiency. Three dogs previously trained for customs quarantine were retrained to detect the scents of red imported fire ants. After passing tests involving different numbers of live red imported fire ants and three other ant species--Crematogaster rogenhoferi Mayr, Paratrechina longicornis Latreille, and Pheidole megacephala F.--placed in containers, ajoint field survey for red imported fire ant nests by detection dogs and bait traps was conducted to demonstrate their use as a supplement to conventional detection methods. The most significant findings in this report are (1) with 10 or more red imported fire ants in scent containers, the dogs had >98% chance in tracing the red imported fire ant. Upon the introduction of other ant species, the dogs still achieved on average, a 93% correct red imported fire ant indication rate. Moreover, the dogs demonstrated great competence in pinpointing emerging and smaller red imported fire ant nests in red imported fire ant-infested areas that had been previously confirmed by bait trap stations. (2) Along with the bait trap method, we also discovered that approximately 90% of red imported fire ants foraged within a distance of 14 m away from their nests. The results prove detection dogs to be most effective for red imported fire ant control in areas that have been previously treated with pesticides and therefore containing a low density of remaining red imported fire ant nests. Furthermore, as a complement to other red imported fire ant monitoring methods, this strategy will significantly increase the efficacy of red imported fire ant control in cases of individual mount treatment.

Sequence variations and phylogenetic relationships of Strumigenys from different localities in Taiwan were inferred from sequences of the internal transcribed spacer 2 (ITS2) of nuclear ribosomal RNA genes. The ITS2 sequences of different species of Strumigenys vary in length from 659 to 953 bp, because there are many large repeated insertion-deletion fragments, and these short tandem repeat units form microsatellites. The average GC content of the ITS2 is 60.8%. Secondary structures from ITS2 sequences are similar and present several conserved structural motifs. Eleven species and three unnamed species were analyzed using both the maximum parsimony and maximum likelihood methods. Although diversity of the ITS2 sequence is high, these data can still be a potential tool for primary analysis of molecular phylogeny and biogeography of Strumigenys at the species level on islands around Taiwan., (Copyright 2004 Elsevier Inc.)

Whereas most economic and ecological impacts of tramp ant species stem in large part from numerical dominance and exacerbated aggressiveness of workers, those imposed by alate (winged) ants have been rarely described. In the present study, we report an unprecedented massive alate swarming (i.e., mating flight) event in southern Taiwan by a tramp ant species, Technomyrmex albipes (Smith) (Hymenoptera: Formicidae), that triggers immediate pest management responses, and examine factor(s) that potentially contribute to the remarkably high number of alates. We monitored the seasonal activities of T. albipes workers and phenology of alate swarming, attempting to link the worker foraging dynamics with swarm ontogeny. As it was argued that recent streetlight fixtures converted from high‐pressure sodium to light‐emitting diode (LED) may serve as a major cause of the massive swarming, alates' light color preference was investigated. Sex ratio of trapped alates was also assessed to test whether sex‐specific light preference exists in T. albipes. We showed that foraging intensity of workers increased in the spring, peaked in May, and was followed by the nuptial flight season that began in August and lasted for 4 months. The phenological pattern is consistent with the colony dynamics in many other ant species. Although the two light preference experiments did not yield the same results, T. albipes alates overall preferred lights with shorter wavelengths in the active trapping, partially supporting the argument of white LED streetlights contributing to the massive flight. The sex ratio of trapped alates was overall female‐biased, suggesting female alates are disproportionally produced and/or more sensitive toward lights. [ABSTRACT FROM AUTHOR]

Simple Summary: Similar to wasps and bees, ants also produce their males by parthenogenesis (development from unfertilized eggs). Much more exceptional is thelytoky, which means that female offspring is also produced by parthenogenesis. This phenomenon to date has been reported for only 16 ant species, including three that belong to the genus Strumigenys: S. hexamera, S. membranifera and S. rogeri. In the present study we discovered that thelytoky also occurs in three more Strumigenys species: S. emmae, S. liukueiensis and S. solifontis. Although queens of these thelytokous Strumigenys species do not need sperm to produce female offspring, they all do contain a functional reproductive system. This includes the presence of a spermatheca, which is the storage organ in which queens store the sperm they receive from the males during the mating flight. We hypothesize that these queens retain a spermatheca for the rare event when they encounter a male and mate with it. In several of these thelytokous Strumigenys species, males are extremely rare but are occasionally produced. Mating with such males considerably increases the genetic variability of the offspring in these thelytokous Strumigenys colonies. Several thelytokous species, such as S. emmae, S. membranifera and S. rogeri, are tramp species. It is obvious that reproduction without the need to mate with males offers these species a big advantage when establishing colonies in new environments. Parthenogenetic reproduction is a common feature for social Hymenoptera, as males typically develop from unfertilized eggs (arrhenotoky). Production of female offspring without the involvement of sperm (thelytoky) also exists but is rather exceptional as it has been reported for only 16 ant species so far. Three of these belong to the genus Strumigenys: S. hexamera, S. membranifera and S. rogeri. Our observations on the reproductive biology in various Oriental Strumigenys species extends this list of thelytokous ants with three more species: S. emmae, S. liukueiensis and S. solifontis. Of these six thelotykous species, S. emmae, S. membranifera and S. rogeri are known as tramp species. Reproduction without the need to fertilize eggs no doubt offers these species a considerable advantage when establishing colonies in new environments. Published histological data on S. hexamera and S. membranifera already showed that the queens possess a functional spermatheca. We now provide evidence that this is also the case for the four other thelytokous Strumigenys species. Retaining a functional spermatheca and reproductive system may keep the queens ready for the exceptional event of mating and hence increase genetic variability, as males do occur very rarely. [ABSTRACT FROM AUTHOR]

Studies on the role of natural predatory instincts in captive‐born mammalian myrmecophagy are rare. Consequently, researchers rely extensively on case reports to learn more about the contexts in which predatory behavior occurs among such animals. In this study, we recorded an uncommon case of a captive‐born southern tamandua (Tamandua tetradactyla) that accidentally escaped from a zoo into a nonnative habitat in Asia. The southern tamandua was found alive 3 months later. Two fresh fecal samples were obtained, and the diet composition was examined. Three termite species (one family, three genera), and 14 ant species (four subfamilies, nine genera) were identified in the fecal samples. The studied southern tamandua preyed on terrestrial and arboreal ants and termites, as the wild populations of its species do. Ants of the subfamily Myrmicinae and termites of the subfamily Nasutitermitinae were the most abundant prey items in the samples, which is consistent with related reports on the wild populations. Soldier ants constituted <1% of the prey items in the fecal samples, suggesting that the southern tamandua likely avoided preying on ants of the soldier caste. Fungus‐growing termites Odontotermes (Isoptera: Macrotermitinae), which are not native to neotropical regions, were also ingested by the southern tamandua. This study provides information on how a captive‐born mammalian myrmecophagy applies its natural feeding instincts in nonnative natural settings. [ABSTRACT FROM AUTHOR]

The diet of myrmecophagous mammals is usually studied by investigating the chitinous remains of termites and ants obtained from stomachs, guts, and faeces; however, this process is time and labour intensive. Moreover, faeces of obligate myrmecophagous mammals contain other materials such as soil, sand, rocks, and plant matter, which hinder the accurate and efficient identification of faeces' contents; this makes estimating the biomass of each prey species difficult. This study tested non-filtering and filtering faecal analysis procedures and compared their identification accuracy and efficiency in the analysis of Formosan pangolin Manis pentadactyla pentadactyla faeces. In the non-filtering procedure, 1 g of dried faeces was distributed over an area greater than 360 cm2 to be able to see most ant capsules and termite mandibles. In the filtering procedure, 0.5 cm3 of filtered chitinous remains of termites and ants was spread over a 45 cm2 area to obtain a high resolution of the diet composition. The filtering procedure can sieve out insect remains from the debris, which facilitates further identification of the insect chitin. Using the two proposed faecal analysis procedures, the prey species composition and the number of prey remains could be obtained. Our results provide a quantitative method to evaluate the diversity of wild pangolin's diets for determining their ecological requirements and developing in-situ and ex-situ conservation plans. [ABSTRACT FROM AUTHOR]

Simple Summary: Ants form a diverse group of social insects that are characterized by an overwhelming variety of exocrine glands, that play a key function in the communication system and social organization of the colony. Our focus goes to the genus Strumigenys, that comprise small slow-moving ants that mainly prey on springtails. We discovered a novel gland inside the mandibles of all 22 investigated species, using light and electron microscopy. As the gland occurs close to the base of the mandibles, we name it 'basimandibular gland' according to the putative description given to this mandible region in a publication by the eminent British ant taxonomist Barry Bolton in 1999. The gland exists in both workers and queens and appeared most developed in the queens of Strumigenys mutica. These queens in addition to the basimandibular gland also have a cluster of gland cells near the tip of their mandibles. The queens of this species enter colonies of other Strumigenys species and parasitize on them. We expect that the peculiar development of these glands inside the mandibles of these S. mutica queens plays a role in this parasitic lifestyle, and hope that future research can shed more light on the biology of these ants. In 1999, Barry Bolton postulated the presence of a basimandibular gland in the mandibles in all species of the ant genus Strumigenys, solely based on scanning microscopy observations. We now confirm the presence of this putative gland in the proximal outer part of the mandibles of 22 investigated species by histological and ultrastructural examination, including 10 short- and 12 long-mandibulate species. All species have a basimandibular gland, that is formed by 15–25 µm thick epithelial cells and belongs to class-1 following the standard classification of insect exocrine glands. We consider it a novel gland because of its peculiar bowl-shape and special arrangement of the microvilli that are confined to large vacuolar spaces instead of reaching the cuticle. The gland is most pronounced in S. mutica, particularly in the queen. In addition to this gland, we also found scattered class-3 intramandibular gland cells in the mandibles. Queens of S. mutica are peculiar in having a cluster of these cells in the distal tip of their mandibles. As this species is a social parasite, further research is required to determine whether the development of these mandibular glands is related to its parasitic lifestyle. [ABSTRACT FROM AUTHOR]

We uncovered taxonomic diversity, country of origin and commodity type of intercepted ants at Taiwanese borders based on an 8 year database of 439 interception records. We found intercepted ants arrived predominantly via timber, a pattern likely reflecting the high domestic demand for foreign timber in Taiwan. The most frequently intercepted species were either arboreal or wood-dwelling ants, raising a concern of these ants constituting a next wave of ant invasion in Taiwan. Further analyses indicate that the taxonomic composition of intercepted ants does not match that of established non-native ant species, suggesting that interception data alone fails to provide adequate power to predict the establishment success of ants. Yet, interception frequency and selected life-history traits (i.e., flexible colony founding mode and general nesting habits) were shown to jointly serve as a practical predictor of the establishment risk of non-native ants. Consistent with other border interception databases, secondary introduction (i.e., species arriving from their introduced ranges instead of their native ranges) also represents a major pathway for transport of invasive ants into Taiwan, suggesting its role in shaping the global invasion of ants. Our findings offer baseline information for constructing a prediction framework for future ant invasions and assist in the decision-making process of quarantine authorities in Taiwan. [ABSTRACT FROM AUTHOR]