Background/Question/Methods Modern agriculture creates a mosaic of large monocultures in the landscape with discontinuous resource availability for insect predators both spatially and temporally due to seasonal cropping cycles. Hippodamia convergens is a highly mobile generalist predator feeding on aphids and other agricultural insect pests and an ideal model system to study predator dispersal and reproduction in response to resource variability. We were interested in how discontinuous access to food, such as boom and bust aphid populations and longer patterns of seasonal variation in prey population size, would influences reproduction and flight and the energetic trade-offs between these costly behaviors. Results/Conclusions Our study tested the effects of continuous versus discontinuous access to food on dispersal and reproduction of adult H. convergens beetles, using tethered flight as a proxy for dispersal before and after 18 reproductive days. We provisioned high (12h) and low (6hr) levels of access to prey over 48h periods. These treatments were further split into two availability pattern treatments: concentrated in one day, followed by no food the second day (discontinuous), or split evenly over both days (continuous). We found that more females remained in reproductive diapause on a discontinuous diet and that preoviposition period was extended in females that became reproductive. Longer pre-oviposition periods reduced the number of reproductive days and, due to a negative relationship between preoviposition period and fecundity, resulted in lower realized fitness. Flight behavior and reproductive success were negatively correlated, revealing that past energetic expenditure can deplete future energetic reserves. The negative effects of diet discontinuity at fine temporal scales illustrate how gaps in resource availability affect lady beetle population dynamics and potentially, their ecosystem services in the wider agricultural landscape. Understanding how resource availability patterns affect lady beetle fitness and behavior can inform strategies for agricultural land management that enhance conservation biological control.
