Lady beetles such as Coleomegilla maculata DeGeer and Hippodamia convergens Guerin-Meneville have been categorized as income breeders because egg maturation depends on resources available during reproduction. However, capital resources acquired during larval feeding influence reproductive success via effects on adult body size and other traits. We produced three sizes of beetles by varying larval access to food and subjected mated females to alternating periods of food surplus and deficit. Both species exhibited temporal variation in clutch size that reflected changes in income, the amplitude of fluctuations being greater in H. convergens. Egg mass in C. maculata appeared to increase as a fixed function of oviposition sequence but also was affected by maternal body size, whereas H. convergens egg mass fluctuated more in response to food supply. Fertility was largely unaffected by income fluctuation but appeared constrained by capital, especially in H. convergens. Dynamic changes in reproductive effort (daily mass of eggs/female mass at emergence) mirrored changes in clutch size, the amplitude of fluctuations being greater in H. convergens, the species with higher reproductive effort. Generally, large females compensated for income fluctuations better than small females, likely because of their greater capital and possibly an ability to consume larger meals when food was available. The greater sensitivity to income observed in H. convergens likely reflects a higher degree of aphid-specificity compared with the more generalist C. maculata because effective exploitation of ephemeral aphid outbreaks would favor rapid reproductive responses to changes in food supply.
How to translate text using browser tools
1 April 2013
Trajectories of Reproductive Effort in Coleomegilla maculata andHippodamia convergens (Coleoptera: Coccinellidae) Respond toVariation in Both Income and Capital
German Vargas,
J. P. Michaud,
James R. Nechols
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
Environmental Entomology
Vol. 42 • No. 2
April 2013
Vol. 42 • No. 2
April 2013
clutch size
egg size
fecundity
fertility