Lady beetle oviposition behavior in response to the trophic environment

The food available to coccinellid larvae and their exposure to predation is influenced by where they are placed as eggs. This review examines adult distribution and female oviposition strategies which in turn determine the distribution of coccinellid larvae in habitats. Immigration into a habitat can be influenced by visual and olfactory cues related to habitat quality. Adults are retained in a habitat if sufficient food resources are present. The abundance and quality of food in a habitat affects the reproductive output of a female and survival of larvae. Consequently, there is higher retention and oviposition preference for sites with abundant essential prey. Coccinellids also increase reproduction in response to non-prey foods (i.e., pollen), but avoid ovipositing in areas with copious amounts of honeydew. In laboratory studies, many plant-derived chemicals have been demonstrated to be attractants and oviposition stimulants. The need to place eggs in proximity to food for offspring must be weighed against the risk of cannibalism and intraguild predation. Lady beetles avoid egg predation by reducing oviposition where other adults are present, ovipositing on plants associated with less exposure or incidence of intraguild predation, and avoiding areas with tracks and frass of con- and heterospecific larvae. Indeed, deterrent cues for avoiding predation seem stronger than the positive ones associated with food. An understanding of the resources needed for successful reproduction and larval development in a habitat and the sensory cues that signal these resources, and thus elicit oviposition, may enhance our understanding of the underlying mechanisms affecting coccinellid distribution in habitats.