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The larch woolly adelgid Adelges laricis Vallot (Hemiptera: Adelgidae) infests spruce Picea spp. and larch Larix spp. in the Northern Hemisphere. The present field and laboratory research embraced the hitherto unknown aspects of the biology and ecology of A. laricis on its secondary host, the European larch Larix decidua Mill. in Poland. The study showed that the A. laricis population on L. decidua was represented by exulis sistens females at dwarf stem bases, exulis progrediens mobile 1st instar nymphs (crawlers) on needles, exulis progrediens sessile “woolly” nymphs and “woolly” adults on needles, and winged sexupara females. The maximum abundance of the A. laricis population occurred from the end of April until mid-May, which coincided with the predomination of crawlers in the age structure of the population. The most important limiting weather component was high rainfall, affecting mainly the crawlers. Eight species of Coccinellidae were recorded on adelgid-infested larch trees and Exochomus quadripustulatus (L.) was the dominant species. The main differences in food consumption strategies among adelgid developmental stages were related to the duration of phloem sap ingestion. While the total duration of sap consumption at a given time was similar in all adelgid instars studied, the individual bouts of sap ingestion were much shorter in crawlers than in the sessile forms. The specific probing behavior of the mobile nymphs probably reflects the crawlers’ strategy to evaluate plant sap quality in different phloem vessels. It is likely that such strategy is a behavioral preadaptation for finding abundant food sources for permanent settling before crawlers develop into sessile nymphs and adult females. The feeding strategy of crawlers promotes the rapid dispersal of the population. Therefore, the control of A. laricis on L. decidua should focus on the early stages of the population development, which would most effectively reduce the final damage.

Dinocampus coccinellae (Schrank) is a braconid parasitoid of ladybird beetles (Coleoptera: Coccinellidae) and has exceptionally wide geographical and host ranges. Based on published and unpublished sources Dinocampus coccinellae probably occurs throughout the temperate, subtropical and tropical climatic zones, but some regions, such as sub-Saharan Africa (except its southernmost part) and the Malay Archipelago, have not so far been surveyed for this wasp. In most of its extensive range D. coccinellae was present before the widespread use of classical biological control. It is likely, however, to have reached some oceanic islands and archipelagos at a later date, along with ladybirds used as biocontrol agents. At least 72 species of Coccinellidae are hosts of D. coccinellae. Three of them, Vibidia duodecimguttata (Poda), Calvia decemguttata (L.) and Coccinella miranda Wollaston, are reported here for the first time as hosts of this parasitoid. The most often reported host of D. coccinellae worldwide is Coccinella septempunctata L. followed by Harmonia axyridis (Pallas), Coleomegilla maculata (De Geer) and Hippodamia convergens Guerin.

We investigated food niches, diet diversity and individual food specialization of the larvae and adults of four species of ladybirds, Sospita vigintiguttata (L.), Calvia quindecimguttata (F.), C. quatuordecimguttata (L.) and C. decemguttata (L.), co-occurring in European alder carr forests. The first two species are considered to be strict habitat specialists associated with alders (Alnus spp.) in marshy forests and the other two are less habitat-specialized, inhabiting various deciduous trees and shrubs. Our investigations were based on the analysis of food remains in frass produced by field-collected ladybirds. In each of the species studied, adults had more diversified diets than larvae based on Levins' D index of diversity. The most diverse diet recorded for adults was that for S. vigintiguttata followed by C. quatuordecimguttata, C. quindecimguttata and C. decemguttata. The diversity of larval diet was higher for the habitat specialists, C. quindecimguttata and S. vigintiguttata, than for the more habitat-generalists Calvia decemguttata and C. quatuordecimguttata. Although the main type of prey recorded for both adults and larvae of each of the species studied was aphids, other types of prey made up a relatively high part of the diet of different species/stage combinations. Psylla alni (L.), for example, was frequently recorded in the frass of adults and larvae of S. vigintiguttata and of adults of C. quatuordecimguttata and chrysomelid larvae commonly in the frass of adults and larvae of C. quindecimguttata. Quite a high proportion of the frass of all the species studied contained the remains of Psocodea. The niche width of adults was broader than that of larvae except in C. quindecimguttata in which it was the opposite. The larval niches of the strict habitat specialists, C. quindecimguttata and S. vigintiguttata, were broader than those of the less habitat-specialists C. decemguttata and C. quatuordecimguttata. Adults of all the species studied showed relatively higher levels of food specialization than larvae, except for C. quindecimguttata. The results of this study indicate that ecological specialization is a complex phenomenon and habitat specialization does not imply food specialization.

Dinocampus coccinellae is a parasitoid wasp usually parasitizing ladybird beetles of the tribe Coccinellini. A field survey conducted between March and November 2016 revealed three hosts of this parasitoid in the Srinagar district of the Indian state of Jammu and Kashmir: two members of the Coccinellini (Oenopia conglobata and Coccinella undecimpunctata) and one of the Chilocorini (Priscibrumus uropygialis). Proportion of the latter (atypical) host that were parasitized was 0.09 and intermediate between that recorded for C. undecimpunctata (0.06) and O. conglobata (0.14). A series of laboratory experiments revealed that while a member of Coccinellini (O. conglobata) was more often attacked by D. coccinellae than a member of Chilocorini (P. uropygialis), the proportions of each species from which parasitoids emerged did not differ significantly. There were no significant differences between D. coccinellae females bred from O. conglobata and P. uropygialis, with respect to selection of the two host species and their suitability for the development of the parasitoid. However, members of the Chilocorini other than P. uropygialis (Chilocorus infernalis and Simmondsius pakistanensis) were rarely attacked by D. coccinellae and parasitoid larvae did not emerge from any of those attacked. The results of our experiments indicate that in Kashmir Himalayas D. coccinellae is adapted to parasitize hosts belonging to both Coccinellini and Chilocorini.

Each year huge numbers of adults of Coccinella septempunctata occupy aestivo-hibernation sites on Uludaz Hill, Çimen Mountain in the Kahramanmaraş Province of Turkey. In 2008 and 2009 we investigated the phenology, population dynamics, mortality and natural enemies of C. septempunctata arriving on Uludaz Hill. Samples were collected once a month during the snow-free season (April-November) from the top of the hill (2273 m a.s.l.) and at two lower altitudes (1900 m a.s.l. and 2050 m a.s.l.) on the slopes of the hill. In both years C. septempunctata was clearly more abundant at the top of the hill than at the two lower altitudes, which is in accordance with the hypothesis that beetles migrating to dormancy sites are strongly attracted to sites at the highest altitudes. Numbers of C. septempunctata on the hill were low in April and May. The large increase in abundance recorded in June may be attributed to the arrival of a new generation from lowland breeding sites. Emergence of previous year colonizers from their winter shelters is less probable due to the high fat content of the beetles collected in June. Spring dispersal from the hill to lowland areas was not observed. We suppose that this dispersal was either prevented by low temperature or considerably delayed and not synchronized with the period of ladybird breeding activity in the surrounding lowlands. In addition, the C. septempunctata aestivo-hibernating on Uludaz Hill suffered very high mortality, mainly caused by entomopathogenic fungi of the genus Beauveria. The results of our study are discussed in terms of the ecological trap concept.

Hesperomyces virescens is an ectoparasite of some Coccinellidae, which until the mid-1990s was relatively rarely only reported from warm regions in various parts of the world. Analysis of the host and distribution data of H. virescens recorded in the Western Palaearctic and North America reveals several trends in the occurrence and abundance of H. virescens: (1) it has recently been much more frequently recorded, (2) most of the recent records are for more northerly (colder) localities than the early records and (3) the recent records are mostly of a novel host, the invasive harlequin ladybird (Harmonia axyridis). While in North America H. virescens is almost exclusively found on H. axyridis, all European records of this association are very recent and still less numerous than records of Adalia bipunctata as a host. However, based on a relatively few published cases of the H. axyridis-H. virescens association in Europe and the case described in this paper, it is clear that the harlequin ladybird is currently the main host of this parasite. These changes in the abundance and geographical distribution of H. virescens are probably linked to some features of H. axyridis, such as its abundance, multivoltinism with overlapping generations, high level of promiscuity and overwintering in mass aggregations. The occurrence of these features in one species may make it especially suitable for H. virescens and other parasites that require close contact of host individuals for efficient transmission. Indeed, some of the data indicate that parasites other than H. virescens, like the podapolipid mite Coccipolipus hippodamiae and allantonematid nematodes of the genus Parasitylenchus may also heavily parasitize H. axyridis. We hypothesize that the acquisition of H. axyridis as a host by H. virescens, C. hippodamiae and Parasitylenchus spp. may have further consequences for the abundance and distribution of these parasites, including the expansion of their ranges to other continents colonized by invasive populations of this ladybird and areas in Asia where H. axyridis is native.

In the years 1998-2000, parasitization of the pupae of various ladybird species by scuttle flies of the genus Phalacrotophora was studied in central Poland. Altogether, 12 ladybird species were found to be parasitized by these flies, and one of them, Anatis ocellata (L.), proved to be a host of P. beuki Disney, a species whose biology had not previously been described. Our studies showed that P. beuki can limit the numbers of A. ocellata. In its typical habitat, i.e. Scots pine forests, 35-40% of this ladybird were parasitized by P. beuki. In other habitats, however, where A. ocellata occurred sporadically, P. beuki was not recorded from A. ocellata or other ladybird pupae. P. beuki was described from a single female collected in Holland. The present paper describes the hitherto unknown male, which is very similar to the males of P. berolinensis Schmitz and P. delageae Disney. The feature that reliably separates the males of these three species (a detail of the hypopygium) is described. This feature enabled the recognition in the collection of the Cambridge University Museum of Zoology of a male of P. beuki from Germany, previously assigned to P. berolinensis.

Although there are few studies of the sexual life of coccinellids these phenomena have attracted the interest of isolated groups of coccinellidologists. Probably the most important finding is that at least some coccinellid species (Adalia bipunctata and Harmonia axyridis) do not mate at random with the females prefering certain males. This phenomenon was first observed in Adalia bipunctata by Lusis and then studied in detail by Majerus, O'Donald, de Jong and others. In Japan, Harmonia axyridis was similarly studied by Osawa and Ueno. While the former author found that in this species (as in A. bipunctata) the colour of the elytra is most important in mate choice by females, the latter stresses that size and activity are important. Sperm competition is another interesting phenomenon, most often the sperm of the last male fertilizes the eggs (Ueno, Katakura). Obata and Hidaka have contributed in an important way to elucidating the function of the spermatophore in mating. The studies by Hodek and Ceryngier recorded the maturation and regression of testicular follicles and the relation of mating activity to diapause in four coccinellid species. In contrast to females, where induction of diapause prevents maturation of ovaries, in diapausing males the tissue of testicular follicles remains active until the temperatures decrease in late autumn. Dissection of spermathecae revealed principal difference in autumn mating activity between Coccinella septempunctata, in which 40-60% of the beetles mated before hibernation and Ceratomegilla (syn. Semiadalia) undecimnotata, which does not mate in autumn.

The body length variation, sex ratio, ovarian development and natural enemies (parasitoids and entomopathogenic fungi) of Coccinella septempunctata were studied during two dormancy seasons in three hibernation sites in the Karkonosze mountains: the top of Mt. Śnieżka (1,600 m a.s.l.), the top of Mt. Szrenica (1,360 m a.s.l.) and Karpacz, the village at the foot of Mt. Śnieżka (800 m a.s.l.). The proportion of females and mean body length increased with the altitude of the hibernaculum. Post-diapause maturation of ovaries occurred earlier in spring in females from Karpacz than from the mountain tops. The rate of parasitization of C. septempunctata by its most common parasitoid, the braconid Dinocampus coccinellae, in both seasons exceeded 70% at Karpacz and was 14-28% in the mountain top hibernacula. In contrast, the incidence of fungal infection (mainly by Paecilomyces farinosus and Beauveria bassiana) was higher in beetles overwintering on the two mountain tops.