Low energy reserves and energy allocation decisions affect reproduction by Mountain Pine Beetles,Dendroctonus ponderosae

Abstract

Summary1. Low internal energy reserves at the beginning of the breeding season may impose physiological constraints on an animal's reproductive investment and may alter the optimal trade-off between investment in reproduction and somatic condition. 2. Here we examine how the energetic condition of female Mountain Pine Beetles ( Dendroctonus ponderosae ) affects their reproductive investment. We starved beetles to simulate the decrease in energy that accompanies dispersal and tested whether starved beetles had decreased egg number and decreased egg size, or both. We further distinguished whether changes are due to physiological constraints or shifts in allocation between reproduction and somatic condition. 3. We found that starved beetles produced smaller eggs than non-starved beetles, but females were able to partially offset the energetic deficit by feeding at their breeding habitat. Starvation did not decrease the number of eggs beetles produced. 4. The number and size of eggs produced depended on whether females allocated energy to reproduction or to somatic condition. However, this life-history allocation decision was independent of the amount of energy beetles had at the beginning of reproduction. 5. Our results demonstrate the importance of assessing reproductive investment in the context of other life-history trade-offs. Specifically, since egg size in Mountain Pine Beetles was highly dependent on both the amount of energy remaining after dispersal and whether energy was allocated to reproduction or somatic maintenance, we expect both of these trade-offs to be under strong selection.

Starvation stress during larval development facilitates an adaptive response in adult worker honey bees (Apis mellifera L.)

“…In mammals, under-nutrition or over-nutrition during the prenatal or postnatal period can impact adult reproductive capability (reviewed by Gardner et al, 2009), which may reflect an adaptive adjustment of reproductive strategy (Rae et al, 2002;Rhind, 2004;Jasienska et al, 2006;Kuzawa et al, 2010). In general, a strategy of reducing reproductive investment while increasing somatic maintenance is a typical survival mechanism in insects (Elkin and Reid, 2005;García-Roger et al, 2006).…”

The Effect of Water Limitation on Volatile Emission, Tree Defense Response, and Brood Success of Dendroctonus ponderosae in Two Pine Hosts, Lodgepole, and Jack Pine

“…In this study, maternal galleries in jack pine are also shorter than in lodgepole pine, females reared in jack pine must consume less phloem (thinner phloem and shorter galleries) than those reared in lodgepole pine. Less consumption of nutritious phloem might lead to smaller eggs (Elkin and Reid, 2005), which might result in smaller offspring beetles (McGhehey, 1971), unless jack pine phloem is higher in nutrients.…”

A microsatellite analysis of the western Canadian mountain pine beetle (Dendroctonus ponderosae) epidemic: phylogeography and long distance dispersal patterns

“…as well as maternal investment in eggs (Elkin and Reid, 2005), could be compromised. Identifying source populations producing effective dispersers capable of overcoming the energetic demands of a long flight and of surviving and reproducing in a foreign environment, possibly hundreds of kilometers from their origin, is critical for halting the advance of epidemics.…”