Search

Wolbachia infection is known to affect host reproduction and development. To date, however, the underlying mechanism related to the effects of Wolbachia on host development has not yet been reported. Here, we compared the developmental duration and body weight in different instars of Wolbachia-positive (W+ ) and Wolbachia-negative (W- ) spiders (Hylyphantes graminicola) and detected the relative expression levels of 6 insulin-related genes and 3 ecdysone-related genes using reverse transcription qPCR. Results showed that the developmental duration was significantly shortened in W+ spiders compared with W- spiders. Furthermore, W+ spiders were significantly heavier than W- spiders at the 3rd and 4th instars, although no significant differences in body weight were observed after maturity. We also found that the expression levels of insulin-like growth factor-2 mRNA-binding protein-1, insulin-degrading enzyme, and ecdysone-inducible protein-1 genes were significantly down-regulated in W+ spiders compared with W- spiders, whereas the expression levels of insulin-like growth factor-binding protein-1, insulin-like peptide receptor, insulin receptor substrate 2-B, insulin-like, ecdysone-induced protein-2, and ecdysone receptor genes were significantly up-regulated in W+ spiders. Our results suggest that Wolbachia may influence host development by affecting insulin and ecdysone signaling pathways.

Many arthropods exhibit flower-visiting behavior, including a variety of spider species. However, as spiders are assumed to be strictly predatory, flower-visiting spiders are an often neglected group. We conducted a systematic biodiversity study of flower-visiting spiders based on published papers and field surveys. Most previous studies have focused on the herbivorous behavior of flower-visiting spiders (nectivory or pollinivory) and their effects on host flowers (tritrophic interactions with flower-visiting insects). In our field survey, we utilized standard transect walks (active sampling) and colored pan traps (passive sampling) to investigate species occurrence, diurnal and seasonal variation, and flower color preference of flower-visiting spiders. From the transect walks, crab spider species were found to be the dominant flower-visiting spiders and, based on all spider species, juvenile visitors were significantly more common than adults. Furthermore, in terms of spider number and species richness, tulips were the preferred flower to visit. For the pan traps, wolf spiders were found to be the dominant spider species. No significant differences were observed in the number of spiders caught in different colored pans, suggesting that color may not be an important flower trait in regard to spider preference. To the best of our knowledge, this study is the first to propose the term 'flower-visiting spiders' and conduct a systematic investigation of their diversity. However, this is preliminary research and further studies are required, especially as biodiversity is often closely linked to survey sites and ecotopes.1. Generally speaking, flower-visiting spiders focuses on the herbivorous behavior (nectivory or pollinivory) and their effects on host flowers (tritrophic interactions with flower-visiting insect). 2. The authenticity of flower-visiting spiders collected by active sampling was higher than passive trapping; juvenile spider visitors were significantly more common than adults. 3. Our study is the first to propose the term ‘flower-visiting spiders’, and further research is needed.

Many studies have explored the effects of plastic particles on aquatic organisms. To date, however, few studies have reported on the effects of plastic particles on terrestrial invertebrates. Here, Culex quinquefasciatus (southern house mosquito, prey) and Pardosa pseudoannulata (wolf spider, predator) were used to explore the transmission of nanoplastics (NPs) from aquatic to terrestrial invertebrates and to verify the effects of NPs in prey on predators. Mosquito larvae were exposed to 0, 200, and 1000 NPs mL

Elevated CO

The ladybeetle Propylea japonica is a widely distributed natural enemy in many agricultural systems. P. japonica is often used as a test organism for safety assessments of transgenic Bacillus thuringiensis crops. Plant varieties expressing the Vip3Aa insecticidal protein are not currently commercially available in China. In this study, protease inhibitor E-64 was used as a positive control to examine the responses of P. japonica larvae to a high concentration of Vip3Aa proteins. Larvae that were fed E-64 had increased mortality and prolonged developmental period, but these parameters were unaffected when larvae were fed Vip3Aa. The epithelial cells of midguts were intact and closely connected with the basal membrane when larvae were fed Vip3Aa, but the epithelial cells degenerated in the E-64 treatment. The activities of antioxidative enzymes and expression levels of detoxification-related genes in P. japonica larvae were not altered after exposure to Vip3Aa; however, these biochemical and molecular parameters were significantly changed in the E-64 treatment. The results demonstrate that Vip3Aa protein is not harmful to the predator P. japonica.

Temperature is a critical abiotic factor that causes physiological changes in arthropods. However, little is known about the effect of heat stress on the antioxidant responses of Araneae species. Hylyphantes graminicola is a dominant predator in many cropping systems in China. In the present study, the effect of short-term heat stress (36, 38, 40 or 42 °C) on the reactive oxygen species (ROS) levels, the activities of antioxidant enzymes (superoxide dismutase [SOD], catalase [CAT], peroxidases [POD] and glutathione-S-transferases GST]), total antioxidant capacity (TAC), malondialdehyde (MDA) concentrations and survival of H. graminicola spiderlings and adults were investigated. The results showed that H. graminicola adults had a significantly higher survival rate compared to spiderlings at 40 °C. The heat stress increased ROS contents in H. graminicola. The SOD, CAT, POD and GST activities increased in spiderlings and adults under heat stress. These data suggest a defensive function for these enzymes in alleviating oxidative damage. Specifically, SOD plays a key role in reducing the high level of superoxide radicals in spiderlings and adults. Moreover, the POD and CAT capabilities for scavenging H2O2 in spiderlings were similar, and CAT may play a more important role than POD in scavenging H2O2 in adults at 42 °C. The spiderling TAC increased significantly at 40 and 42 °C, and the adult TAC was stable at 36–40 °C but decreased at 42 °C. These data suggest that TAC was insufficient in H. graminicola adults under more severe stress conditions. These results further our understanding of the physiological response of Araneae species exposed to heat stress.

Phage WO is a bacteriophage found in Wolbachia. Herein, we represent the first phylogenetic study of WOs that infect spiders (Araneae). Seven species of spiders (Araneus alternidens, Nephila clavata, Hylyphantes graminicola, Prosoponoides sinensis, Pholcus crypticolens, Coleosoma octomaculatum, and Nurscia albofasciata) from six families were infected by Wolbachia and WO, followed by comprehensive sequence analysis. Interestingly, WO could be only detected Wolbachia-infected spiders. The relative infection rates of those seven species of spiders were 75, 100, 88.9, 100, 62.5, 72.7, and 100 %, respectively. Our results indicated that both Wolbachia and WO were found in three different body parts of N. clavata, and WO could be passed to the next generation of H. graminicola by vertical transmission. There were three different sequences for WO infected in A. alternidens and two different WO sequences from C. octomaculatum. Only one sequence of WO was found for the other five species of spiders. The discovered sequence of WO ranged from 239 to 311 bp. Phylogenetic tree was generated using maximum likelihood (ML) based on the orf7 gene sequences. According to the phylogenetic tree, WOs in N. clavata and H. graminicola were clustered in the same group. WOs from A. alternidens (WAlt1) and C. octomaculatum (WOct2) were closely related to another clade, whereas WO in P. sinensis was classified as a sole cluster.

According to sexual selection theory, age affects the preference of mate choice, and this preference ultimately influences the fecundity of the female. Pardosa pseudoannulata (Araneae: Lycosidae) is a valued predator in many cropping systems. By determining oviposition rate, egg hatching rate, and also the number and carapace width of the 2nd instar spiderlings of the F1 generation, we explored the effects of age on fecundity of the female spider. There were no significant effects of age on courtship duration, sexual cannibalism rate, mating rate, oviposition rate, egg hatching rate, or the number and carapace width of 2nd instar spiderings of P. pseudoannulata. However, age had a significant effect on courtship latency, courtship intensity, and mating duration of the spider. Courtship latency decreased significantly with an increase in the age of the male, and courtship intensity of the low-age male increased with increasing female age. Increasing age of male and female spiders was associated with significantly prolonged mating duration. The results indicated that low-age male spiders were more inclined to mate with high-age females, and age had no significant effect on sexual cannibalism rate or the fecundity of the female.

Associations between endosymbiotic bacteria and their hosts are widespread in nature and have been demonstrated extensively; however, only a few studies have examined how facultative symbionts affect host nutrition and metabolism. To gain insight into the associations between facultative symbionts and host nutrition and metabolic activity, we detected endosymbiotic infection in a small spider species, Hylyphantes graminicola, and established two infectious strains, i.e., W−C+ (Wolbachia negative, Cardinium positive) and W+C+ (Wolbachia positive, Cardinium positive). We then determined the content of fat and free amino acids in W−C+ and W+C+ spiders, respectively. We also detected the transcriptome of H. graminicola and the expression of genes involved in fat and amino acid metabolism at different host ages. Results showed that fat content in W+C+ spiders was higher than that in W−C+ spiders, and free amino acid content was higher in W+C+ males than W−C+ males, with no difference observed in females. Transcriptome analysis identified 144 (W−C+ vs W+C+) differentially expressed genes (DEGs). Moreover, the expression of five genes involved in fat and amino acid metabolism were significantly up-regulated in the third, fourth, and fifth instar stages in W+C+ spiders. This study indicated that Wolbachia and Cardinium co-infection had a pivotal effect on fat and amino acid synthesis in hosts. Moreover, our results provide strong evidence explaining the long-term coexistence of hosts and endosymbionts.

Pardosa pseudoannulata is one of the most common wandering spiders in agricultural fields and a potentially good bioindicator for heavy metal contamination. However, little is known about the mechanism by which spiders respond to heavy metals at the molecular level. In this study, high-throughput transcriptome sequencing was employed to characterize the de novo transcriptome of the spiders and to identify differentially expressed genes (DEGs) after cadmium exposure. We obtained 60,489 assembled unigenes, 18,773 of which were annotated in the public databases. Ultimately, 3450 cDNA simple sequence repeats were identified and validated as potential molecular markers in the unigenes. A total of 2939, 2491 and 3759 DEGs were detected among the three libraries of two Cd-treated groups and the control. Functional enrichment analysis revealed that metabolism processes and digestive system function were predominately enriched in response to Cd stress. At the cellular and molecular levels, significantly enriched pathways in lysosomes and phagosomes as well as replication, recombination and repair demonstrated that oxidative damage resulted from Cd exposure. Based on the selected DEGs, certain critical genes involved in defence and detoxification were analysed. These results may elucidate the molecular mechanism underlying spiders' responses to heavy metal stress.

The Wolbachia endosymbiont of spiders has not been extensively examined. In order to investigate the distribution, evolutionary history, and reproductive phenotype of Wolbachia in spiders in China, we tested 11 geographic populations of Hylyphantes graminicola. Wolbachia infection has been detected in each population. 10 Wolbachia strains have been characterized by multilocus sequence typing (MLST). Phylogenetic analyses indicated that eight Wolbachia strains in H. graminicola belonged to supergroup B, and two belonged to supergroup A. No correlation existed between Wolbachia diversity and host's geographic distance. The significant correlation was observed between pairwise distance of H. graminicola COI and genetic divergence of associated Wolbachia strains. We also found that Wolbachia infection frequencies in hosts varied over geographic space.

The objective of the present study was to assess the ecotoxicological responses of Pardosa pseudoannulata to a common environmental pollutant, cadmium. Third-instar spiderlings and adult spiders were exposed to sublethal concentrations of CdCl2 solution in their drinking water. The Cd content in P. pseudoannulata adults increased significantly with the number of days of exposure to a 0.2 mM CdCl2 solution, when exposed to 2 mM CdCl2 solution, the Cd content in the spiders increased sharply in the first two (male) or three (female) weeks, and then no significant changes were recorded following with the next three (male) or two (female) weeks exposure. Exposure of spiders to Cd contaminated drinking water resulted in reduced body mass, delayed development, fewer eggs and increased mortality. Significantly higher activities of superoxide dismutase, catalase and glutathione-s-transferase were recorded in the spiders after 7 day exposure to 0.2 mM CdCl2 solution. However, longer-term exposures or increased Cd concentrations did not result in significantly higher antioxidant enzyme activity relative to control treatment.

This study investigated the bioaccumulation and effects of mercury (Hg) in funnel-web spiders, Agelena labyrinthica, following exposure to sublethal concentrations of Hg(NO3)2 in their drinking water. The results showed that the Hg content in adult A. labyrinthica increased rapidly with the number of days exposed to the Hg(NO3)2 solution, and the mortality of adult spiders within 30 days increased with increased concentrations of Hg(NO3)2 in the drinking water. The total developmental duration of A. labyrinthica exposed to Hg(NO3)2 was significantly longer than in the control spiders, but there were no significant differences in the total developmental duration of spiders among the three treatment groups (exposed to 10, 20 and 50 mg/L Hg(NO3)2 solution). We also compared the web-weaving of the control and treated spiders, and found no significant differences in shape, structure, color, or size of the webs between the control and treated spiders; however, there was a significant difference in web placement between the treatment and control groups. The spiders in the control group appeared to have an episodic-like memory, choosing to weave their five webs in the same corner in the five time periods allowed.