To avoid predation, prey initiate anti-predator defenses such as altered behavior, physiology and/or morphology. Prey trait changes in response to perceived predation risk can influence several aspects of prey biology that collectively contribute to individual success and thus population growth. However, studies often focus on single trait changes in a discrete life stage or morphotype. We assessed how predation risk by Harmonia axyridis affects several important traits in the aphid, Myzus persicae: host plant preference, fecundity and investment in dispersal. Importantly, we examined whether these traits changed in a similar way between winged (alate) and wingless (apterous) adult aphid morphotypes, which differ in morphology, but also in life-history characteristics important for reproduction and dispersal. Host plant preference was influenced by the presence of H.axyridis odors in choice tests; wingless aphids were deterred by the odor of plants with H.axyridis whereas winged aphids preferred plants with H.axyridis present. Wingless aphids reared in the presence of ladybeetle cues produced fewer offspring in the short-term, but significantly more when reared with exposure to predator cues for multiple generations. However, winged aphid fecundity was unaffected by H.axyridis cues. Lastly, transgenerational plasticity was demonstrated in response to predation risk via increased formation of winged aphid morphotypes in the offspring of predator cue-exposed wingless mothers. Importantly, we found that responses to risk differ across aphid polyphenism and that plasticity in aphid morphology occurs in response to predation risk. Together our results highlight the importance of considering how predation risk affects multiple life stages and morphotypes.

Bumble bees (genus Bombus) includes approximately 250 social species, many of which are in decline in North America and Europe. To estimate colony abundance of bumble bees in natural and agricultural habitats, sib-ship relationships are often reconstructed from genetic data with the assumption that colonies have one monogamous queen. However, some species such as the common Eastern North American bumble bee (Bombus impatiens) can display low levels of polyandry that can bias estimates of colony abundance based on sib-ship reconstructions. In order to accurately quantify rates of polyandry in this species, we empirically estimated mating frequencies of queens using a novel statistical model and genotypes from 730 bees. To genotype individuals, we used a highly polymorphic microsatellite set for colonies established from 20 wild caught and 10 commercial queens. We found multiple fathers in 15% of wild colonies and 30% of commercial colonies. This resulted in average effective mating frequencies of 1.07 for wild and 1.15 for commercial colonies. Paternity was also skewed, with the 2nd or 3rd father contributing less than 30% of the offspring. These findings agree with previous reports of polyandry for B. impatiens. Using a large empirical dataset, we demonstrate that assuming monogamy for colony abundance estimation in species that violate this assumption may result in a vast overestimation of the number of colonies. Our results emphasize the importance of studying mating frequencies in social species of conservation concern for the appropriate implementation of genetic approaches for colony abundance estimation.

To avoid predation, prey initiate anti-predator defenses such as altered behavior, physiology and/or morphology. Prey trait changes in response to perceived predation risk can influence several aspects of prey biology that collectively contribute to individual success and thus population growth. However, studies often focus on single trait changes in a discrete life stage or morphotype. We assessed how predation risk by Harmonia axyridis affects several important traits in the aphid, Myzus persicae: host plant preference, fecundity and investment in dispersal. Importantly, we examined whether these traits changed in a similar way between winged (alate) and wingless (apterous) adult aphid morphotypes, which differ in morphology, but also in life-history characteristics important for reproduction and dispersal. Host plant preference was influenced by the presence of H.axyridis odors in choice tests; wingless aphids were deterred by the odor of plants with H.axyridis whereas winged aphids preferred plants with H.axyridis present. Wingless aphids reared in the presence of ladybeetle cues produced fewer offspring in the short-term, but significantly more when reared with exposure to predator cues for multiple generations. However, winged aphid fecundity was unaffected by H.axyridis cues. Lastly, transgenerational plasticity was demonstrated in response to predation risk via increased formation of winged aphid morphotypes in the offspring of predator cue-exposed wingless mothers. Importantly, we found that responses to risk differ across aphid polyphenism and that plasticity in aphid morphology occurs in response to predation risk. Together our results highlight the importance of considering how predation risk affects multiple life stages and morphotypes.