The Influence of Conspecific Males on Spermatophore Deposition in the Eriophyid Mite Aculus Fockeui

Similarly to males of Aculus fockeui on plum, males inhabiting peach showed interest in quiescent female nymphs and behaved non-aggressively in contact with each other. When maintained on fresh leaf arenas for 5h, males in groups of seven deposited significantly fewer spermatophores per male than solitary ones. The inhibitory effect of the presence of conspecific males on spermatophore deposition rate is indicated and discussed in the context of previous opposite observations on this mite.     

First copulation increases longevity and fecundity of <Emphasis Type="Italic">Histiostoma feroniarum</Emphasis> (Acari: Astigmata: Acaridida) females

I investigated the influence of insemination at different life stages on female fitness in the mite Histiostoma feroniarum. In this species, males guard immature females at the tritonymph stage to inseminate them immediately after the last moulting. Four groups of females were studied (1) females inseminated naturally, i.e. mating occurred immediately after guarding, and then the male was removed (IF/0M), (2) naturally inseminated females, where after insemination the male was replaced by two additional males (IF/2M), (3) virgin females reared without males (VF/0M) and (4) mature, virgin females to which two virgin males were added 3 days after last moulting (VF/2DM). The results show that females inseminated naturally (IF/0M) have higher longevity and fecundity than either virgin (VF/0M) or late-inseminated females (VF/2DM). Furthermore, longevity and fecundity of the former (IF/0M) was also greater than that of females naturally inseminated and subsequently exposed to males (IF/2M). One may suggest that seminal fluids have a positive effect on female fitness. When delayed insemination occurs, such positive effect may not be observed due to a change in features of the sperm access system. Harassment may explain decreased longevity and fecundity of females inseminated naturally compared to females that received additional males.This revised version was published online in May 2005 with a corrected cover date.     

How predatory mites find plants with whitefly prey

We investigated the searching behaviour of two species of predatory mites, Typhlodromips swirskii (Athias-Henriot) and Euseius scutalis (Athias-Henriot), both known to feed on immature stages of the whitefly Bemisia tabaci Gennadius. When released in a greenhouse inside a circle of cucumber plants that were alternatingly clean or infested with immature whiteflies, the mites took several days to find plants. Both species were recaptured significantly more on plants with whiteflies. This suggests that the mites are able to discriminate between plants with and without whiteflies. The predators may either have been attracted to plants with whiteflies from a distance or arrested on plants with whiteflies. Typhlodromips swirskii that had previously fed on whitefly immatures on cucumber leaves were significantly attracted by volatiles from cucumber plants with whiteflies in a Y-tube olfactometer. This suggests that the mites use volatile cues to discriminate between infested and clean plants. However, this response waned rapidly; if predators, experienced as above, were starved for 3–4 h in absence of cucumber leaves, they no longer preferred volatiles of infested plants to clean plants. Furthermore, T. swirskii that had no experience with immature whiteflies on cucumber plants also did not prefer odours of infested plants to those of clean plants. Because the release experiment with this species in the greenhouse was done with inexperienced predators, this suggests that the aggregation of mites on plants with whiteflies was mainly caused by differential arrestment of mites on plants with prey and clean plants. For T. swirskii, this was in agreement with the finding that the fraction of predators on plants with prey increased with time to levels higher than 70%. A less clear trend was found for E. scutalis, for which the fraction of predators on plants with prey stabilized soon after release to levels from 54–70%. Hence, the predatory mites may find plants with prey by random searching, but they are subsequently arrested on these plants. An earlier study showed that 87% of all whiteflies released in a set-up as used here were recaptured within 1 day. Hence, the effectiveness with which predatory mites locate plants with whiteflies is low compared with that of their prey. We expect this to generate spatial patterns in the dynamics of predator and prey and this may have consequences for biological control of whiteflies with predatory mites.     

Oribatid mite (Acari, Oribatida) feeding on ectomycorrhizal fungi

The coexistence of a large number of soil animals without extensive niche differentiation is one of the great riddles in soil biology. The main aim of this study was to explore the importance of partitioning of food resources for the high diversity of micro-arthropods in soil. In addition, we investigated if ectomycorrhizal fungi are preferentially consumed compared to saprotrophic fungi. Until today, ectomycorrhizal fungi have never been tested as potential food resource for oribatid mites. We offered six ectomycorrhizal fungi [Amanita muscaria (L.) Hook., Boletus badius (Fr.) Fr., Cenococcum geophilum Fr., Laccaria laccata (Scop.) Fr., Paxillus involutus (Batsch) Fr. and Piloderma croceum J. Erikss. & Hjortstam], one ericoid mycorrhizal fungus [Hymenoscyphus ericae (D.J. Read) Korf & Kernan] and three saprotrophic fungi [Agrocybe gibberosa (Fr.) Fayod, Alternaria alternata (Fr.) Keissl. and Mortierella ramanniana (A. Møller) Linnem.] simultaneously to each of the mainly mycophagous oribatid mite species Carabodes femoralis (Nicolet), Nothrus silvestris Nicolet and Oribatula tibialis Nicolet. The ericoid mycorrhizal fungus H. ericae and the ectomycorrhizal fungus B. badius were preferentially consumed by each oribatid mite species. However, feeding preferences differed significantly between the three species, with O. tibialis being most selective. This study for the first time documented that oribatid mites feed on certain ectomycorrhizal fungi.     

Variation in intensity of a parasitic mite (Spinturnix myoti) in relation to the reproductive cycle and immunocompetence of its bat host (Myotis myotis)

Given the intimate association in host–parasite systems, parasites are expected to initiate their own reproduction when vulnerable hosts become abundant and/or when adult hosts are less resistant. In this study, we examined the variation in the intensities of a blood-sucking mite ( Spinturnix myoti , Acarina) with respect to the reproductive cycle and immunocompetence of its host, the greater mouse-eared bat Myotis myotis . Reproductive, pregnant females were less immunocompetent and harboured more parasites than nonreproductive females, whilst, during lactation, immunocompetence was positively associated with female body mass. There was a dramatic increase in the T-cell response of gravid females with the advancement of gestation, which coincided with a diminution of individual parasite loads and a progressive switch of parasites from adults to juveniles. The latter not only harboured greater numbers of mites than adult female bats, but they also exhibited gravid parasites in higher proportions, indicating that juvenile hosts are more attractive for parasite reproduction than adult females.     

Four new feather mite species of the genus Proctophyllodes Robin(Astigmata:Proctophyllodidae) from China

Four new species of the feather mite genus Proctophyllodes are described from the birds of the order Passeriformes in China:P.flexuosa sp.nov.from Eophona migratoria Hartert(Chongqing),P.brevis sp.nov.from Passer montanus(Linnaeus)(Anhui and Chongqing),P.garrula sp.nov.from Garrulax poecilorhynchus Gould(Anhui),P.canora sp.nov.from Garrulax canorus(Linnaeus)(Guizhou).     

Patterns of diversity and abundance of fleas and mites in the Neotropics: host‐related,parasite‐related and environment‐related factors

The effects of host‐related, parasite‐related and environmental factors on the diversity and abundance of two ectoparasite taxa, fleas (Insecta: Siphonaptera) and mites (Acari: Mesostigmata), parasitic on small mammals (rodents and marsupials), were studied in different localities across Brazil. A stronger effect of host‐related factors on flea than on mite assemblages, and a stronger effect of environmental factors on mite than on flea assemblages were predicted. In addition, the effects of parasite‐related factors on flea and mite diversity and abundance were predicted to manifest mainly at the scale of infracommunities, whereas the effects of host‐related and environmental factors were predicted to manifest mainly at the scale of component and compound communities. This study found that, in general, diversity and abundance of flea and mite assemblages at two lower hierarchical levels (infracommunities and component communities) were affected by host‐related, parasite‐related and environmental factors, and compound communities were affected mainly by host‐related and environmental factors. The effects of factors differed between fleas and mites: in fleas, community structure and abundance depended on host diversity to a greater extent than in mites. In addition, the effects of factors differed among parasite assemblages harboured by different host species.