Journal of Insect Behavior最新文献

Mate discrimination contributes to the co-existence of related species by reducing the risk of interspecific copulation. In pollination mutualistic systems where pollinators utilize host plants as mating places, sharing of host plants with other related species could increase non-adaptive interspecific copulation. Although such host-sharing species are expected to have strong mate discrimination systems, little is known about whether and how they discriminate species for mating. Here, we investigate mate discrimination of two fly species, Colocasiomyia xenalocasiae and C. alocasiae (Diptera: Drosophilidae), which share host plants; they are essentially anthophilous, depending exclusively on specific aroid host plants throughout their entire life cycles. Our field observations showed that the males of C. alocasiae and C. xenalocasiae preferentially paired with conspecific, but not heterospecific, females. This indicates that they discriminate species for mating in the natural habitat. Such mate discrimination was also observed under laboratory conditions. To investigate how these flies discriminate species, we defined distinct behavioral elements in courtship sequence in both species, and compared sexual interactions in each element between conspecific and heterospecific pairs. We found that males discriminate female whilst tapping, whereas females discriminate male before or during males’ attempted mounting. This suggests that mate discrimination systems in both males and females reduce the incidence of heterospecific mounting; mounting is a necessary step in the sequence of courtship for successful copulation. The mate discrimination system found in this study potentially allows for the co-existence of C. xenalocasiae and C. alocasiae on the same host plant by effectively suppressing interspecific copulation.

Bumble bees (Bombus; Hymenoptera) are crucial pollinators for many agricultural crops, but their numbers have declined - with climate change as a possible driver. Different aspects of local weather conditions can have substantial effects on bumble bees’ ability to forage. Here we made 501 observations of bumblebee workers on bramble flowers (Rubus fruticosus) to explore how the characteristic sizes of foragers active and their individual rate of movement between flowers were correlated with aspects of weather. Firstly, we found that increased ambient temperature is correlated to reduced activity in larger workers. Moreover, while higher humidity was linked to an increase in smaller workers, an increase in cloud cover led their numbers to decrease. Visitation rate and temperature showed a significant negative relationship whereas no other weather aspect affected visitation rate significantly. Our results suggest that predicted rises in ambient temperatures will adversely affect bumble bee foraging, and particularly so for larger-bodied workers. We anticipate that this study can be used as a foundation for longer-term and more detailed studies on bumble bee foraging and colony performance. Such work is vital to identify management measures to mitigate pollinator declines and preserve food security.

Although human skin odor is thought to be the cue that anthropophilic mosquitoes use to discriminate us from other potential hosts, the precise details of how they use skin odor to find and land on a human is unclear. We found that Aedes aegypti land on a source of skin odor without a co-located visual cue. By collecting human odor on glass beads and using identical glass beads to visually conceal skin odor and heat cues, we were able to study mosquito landing on skin odor, heat, and visual cues separately. Landing is necessary for blood feeding which is a required behavior for the Aedes aegypti life cycle as well as the behavior responsible for the epidemiological impact of mosquitoes. Therefore, we consider it to be the diagnostic measure of the importance of a host cue. In two-choice tests, a skin odor source had the highest valence for landing, followed by a combination of heat and a visual cue, and finally heat and visual cues presented separately. We also measured the durations of the landings, though no significant differences were found.

Supplementary information: The online version contains supplementary material available at 10.1007/s10905-022-09796-2.