High-quality host plant diets partially rescue female fecundity from a poor early start

Abstract

Nutrition is a dynamic environmental factor and compensatory growth may help animals handle seasonal fluctuations in their diets. Yet, how the dynamic changes in nutrition affect female reproduction is understudied. We took advantage of a specialist insect herbivore, Narnia femorata Stål (Hemiptera: Coreidae), that feeds and reproduces on cactus across three seasons. We first examined how cactus quality can affect female reproductive success. Then, we investigated the extent to which reproductive success can be improved by a switch in diet quality at adulthood. We placed N. femorata juveniles onto prickly pear cactus pads with early-season (low-quality) or late-season (high-quality) fruit and tracked survivorship and development time. A subset of the females raised on low-quality diets were provided with an improved adult diet to simulate a seasonal change in diet. Adult female survival and egg production were tracked over time. All fitness-related traits were lower for females fed low-quality diets compared with females fed high-quality diets. However, when females had access to an improved adult diet, egg production was partially rescued. These findings show that a seasonal improvement in diet can enhance reproduction, but juvenile nutrition still has lasting effects that females cannot overcome.

Seasonal host shifts based on midgut residues of Protaetia brevitarsis

“…However, interestingly, in the present study, nearly two-thirds of the P. brevitarsis adults fed on one plant species during its peak period, while the other one-third fed on 2-4 plant species. Although malnutrition early in life can negatively impact insect health, nutritional supplementation later in life can offset or compensate for the early negative impact [40][41][42]. Therefore, feeding on multiple species might provide missing nutrients to help adults survive their long adult stage and reproduce.…”