Adaptive egg size plasticity for larval competition and its limits in the seed beetleCallosobruchus chinensis

Abstract

Life‐history theory predicts that females who experienced stressful conditions, such as larval competition or malnutrition, should increase their investment in individual offspring to increase offspring fitness (the adaptive parental hypothesis). In contrast, it has been shown that when females were reared under stressful conditions, they become smaller, which consequently decreases egg size (the parental stress hypothesis). To test whether females adjust their egg volume depending on larval competition, independent of maternal body mass constraint, we used a pest species of stored adzuki beans, Callosobruchus chinensis (L.) (Coleoptera: Chrysomelidae: Bruchinae). The eggs of females reared with competitors were smaller than those of females reared alone, supporting the parental stress hypothesis; however, correcting for female body size, females reared with competitors produced larger eggs than those reared in the absence of competition, supporting the adaptive parental hypothesis, as predicted. The phenotypic plasticity in females' investment in each offspring in stressful environments counteracts the constraint of body size on egg size.

Morphology and distribution of antennal, maxillary palp and labial palp sensilla of the adult bruchid beetles,Callosobruchus chinensis(L.) (Coleoptera: Bruchidae)

“…It displays a cosmopolitan distribution pattern and has been spotted in most countries due to the commercial export of beans (Yanagi et al . ).…”

“…It causes not only quantitative but also qualitative losses like nutritive loss and germination loss (Rees 2004;Chakraborty et al 2015). It displays a cosmopolitan distribution pattern and has been spotted in most countries due to the commercial export of beans (Yanagi et al 2013).…”

The interaction effect between intraspecific competition and seed quality on the life‐history traits of the seed‐feeding beetleAcanthoscelides macrophthalmus

“…For instance, female fecundity of the bruchine beetle Callosobruchus maculatus (Fabricius) decreased in the presence of competition, although the changes in body size were not observed, suggesting that there was a lack of some essential nutrient for egg production, but not for larval growth (Colegrave, ; Vamosi & Lesack, ). On the other hand, Yanagi et al () observed that females of the bruchine Callosobruchus chinensis (L.) weighed less, produced fewer offspring and laid smaller eggs when they were reared in the presence of intraspecific competition. However, after correcting for body size (i.e., specifying a particular body mass), the authors found that females produced larger eggs in the presence of competition, suggesting that they may produce larger eggs to increase larval survival despite their reduction in body mass.…”

Bioactive Potentials of <i>Cleome viscosa</i> L. Extracts: Dose-mortality, Insect Repellency and Brine Shrimp Lethality

“…It possesses egg, larva, pupa and adult stage in its life cycle. Pulse beetle is one of the most damaging to the stored legumes industry due to their generalized legume diets and wide distribution [13]. A. salina is a species of aquatic crustaceans also known as brine shrimp.…”