Mite choice generates sex- and size-biased infection inDrosophila hydei

Abstract

Heterogeneities in parasite infection among conspecific hosts often manifest as sex- or size-biased infections, which are typically attributed to differential host susceptibility and exposure. Since parasite fitness is often tied to host quality, host preference by parasites is likely to be under strong selection. We test the hypothesis that host preference is sufficient to generate variability in infection rate among conspecifics. Specifically, we ask whether the mite Macrocheles muscaedomesticae is able to discriminate between Drosophila hydei hosts of different sex and size, while explicitly accounting for the potential confounding effects of these two factors. Our results indicate a preference for female hosts, but this preference appears to be driven by size and not sex per se. When differences in body size were controlled for, the sex-biased infection disappeared, while mites presented with the choice of two female flies of disparate sizes were more likely to select the larger host. Across the distribution of fly body weight in this study, mites preferentially attached to flies of intermediate size. This study provides evidence that mite choice for certain host types can play an important role in parasite transmission, even in the absence of differential susceptibility or exposure among hosts.

Fitness costs of phoretic nematodes in the burying beetle, Nicrophorus vespilloides

“…In addition, the strong sex bias in nematode densities both in the field (Figure 1) and in the laboratory (Figure 4) is consistent with the idea that worms are maximizing dispersal potential by preferentially associating with the sex most likely to colonize a breeding resource (a carcass). Similar biases have been observed in other phoretic nematodes (Krishnan et al, 2010;Scheffer et al, 2013) and mites (Campbell & Luong, 2016;Fronhofer et al, 2013;Gilburn, Stewart, & Edward, 2009). Our field collections reveal that this species is maintained in high, although variable, densities in male and female wild beetles (Figure 1) while further studies in the benign conditions of the laboratory (YW unpublished) have shown that they are also stably maintained within laboratory populations of burying beetles at even higher densities.…”

“…It involves standing upright and waving in all directions, thereby attracting potential hosts (Brown, D'Anna, & Sommer, 2011). Similar biases have been observed in other phoretic nematodes (Krishnan et al, 2010;Scheffer et al, 2013) and mites (Campbell & Luong, 2016;Fronhofer et al, 2013;Gilburn, Stewart, & Edward, 2009). Similar biases have been observed in other phoretic nematodes (Krishnan et al, 2010;Scheffer et al, 2013) and mites (Campbell & Luong, 2016;Fronhofer et al, 2013;Gilburn, Stewart, & Edward, 2009).…”

Mite‐y bees: bumble bees (Bombus spp., Hymenoptera: Apidae) host a relatively homogeneous mite (Acari) community, shaped by bee species identity but not by geographic proximity

“…Although we do not have a direct measure of emergence times in our area, B. rufocinctus is generally the latest to emerge among the bumble bees found in our study (Colla, 2016). Bee body size could also play a role, given that some mite species favour larger insect hosts (Grossman & Smith, 2008;Campbell & Luong, 2016). 2).…”

“…Colony size probably also affects the microclimate and the food supply in the nest, which in turn may affect mite populations. Bee body size could also play a role, given that some mite species favour larger insect hosts (Grossman & Smith, 2008;Campbell & Luong, 2016). Future studies could usefully examine the role of body size and other host species traits and nest attributes -independent of host species identity -in shaping communities of bee-associated mites.…”

Phenotypic plasticity more essential to maintaining variation in host-attachment behaviour than evolutionary trade-offs in a facultatively parasitic mite

“…observation). Their attachment behaviour is plastic and influenced by their own internal state (Jalil and Rodriguez, 1970; Luong et al ., 2017), the state of their potential hosts (Farish and Axtell, 1971; Campbell and Luong, 2016; Luong et al ., 2017) as well as the external environment (Farish and Axtell, 1971; Durkin and Luong, 2018).…”