How does egg size relate to body size in butterflies?
ABSTRACT Although arthropod egg size is an evolutionarily and ecologically significant trait, there is still a poor understanding of the specific factors determining it. For butterflies there is evidence from an interspecific comparison that egg size is related to adult size, suggesting a morphological constraint. Using laboratory populations of the tropical butterfly Bicyclus anynana, we show that larger eggs produce larger hatchlings, and that there is considerable intra-populational variation in egg size. However, the correlation between egg size and female size is weak and explains only 1% of the variation found within a population; even development time is a slightly better predictor for egg size than female size. We conclude that there is no evidence that body size imposes a constraint on the evolution of egg size within butterfly populations. However, populations that have diverged in body size under artificial selection show correlated responses in egg size. Thus, correlations between body size and egg size may represent an emergent property, visible only when a large range of differences in body size is considered.
- American Naturalist - AMER NATURALIST. 01/1987; 130(6).
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ABSTRACT: There is striking variation in egg size among Lepidoptera. Part of the explanation could be a link between egg size and larval feeding ecology.The relationship between absolute egg size and aspects of feeding ecology for different Lepidoptera families from different temperate regions is examined. Species that overwinter in the egg stage have larger eggs. There are significant differences in egg size with respect to feeding specificity but different families show different patterns. Woody plant feeders have larger eggs than herb feeders. There is little effect of proximity of the egg to the plant part that is eaten.Patterns in the behaviour and survival of newly hatched larvae of 42 spp. of British Lepidoptera and their relationship to egg and larval size and to food plant characteristics are examined. Patterns in egg size with respect to feeding ecology are similar to those described above. There is a strong correlation between egg size and the size of newly hatched larvae. Newly hatched larvae survived for a mean of 1–20 days without food. Survival is not correlated with larval weight. Grass feeders survive longer than herb and woody plant feeders; the species surviving the longest feeds on lichens. Newly hatched larvae moved at a mean speed of 0.7-267.8 cm h-1. Speed is not correlated with larval weight or survival time. Grass feeders move faster than woody plant feeders which, in turn, move faster than herb feeders. Woody plant feeders tend to move upwards, grass feeders downwards and herb feeders both upwards and downwards. The proportion of larvae silking is negatively correlated with larval weight.The strong links between egg size and larval feeding ecology and between feeding ecology and larval behaviour are discussed. It is surprising that larval body size does not appear to constrain the speed of movement, nor tolerance to starvation.Journal of Zoology 05/1992; 227(2):277 - 297. · 2.04 Impact Factor
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ABSTRACT: We studied the allocation of total egg mass to size and number in the carabid beetle Notiophilus biguttatus F. at several temperature and day length regimes. Eggs increase in number and decrease in size with increasing (constant) temperature. Day length interacts with temperature: at short day the effect of temperature on size and number of eggs is weaker than at long day. In diurnally fluctuating temperature regimes, egg size is affected disproportionately by the high temperature period. All treatments, however, are similar in affecting number and size of eggs in an opposite direction. Consequently, egg size is explained to a high degree by egg production rate. The relationship between size and number of eggs among treatments is furthermore characterized by a decrease in egg size with an increase in total egg mass production. Within treatments, rate of egg production and egg size are negatively correlated among females in the low-temperature groups but not in the high-temperature groups; the correlations among females are also characterized by a decrease in egg size, with an increase in total egg mass production. Hence, possible trade-offs between size and number of eggs are masked by phenotypic variation in reproductive effort. The observations enable us to propose a simple conceptual model that explains the within-treatment correlation by the same causal factor as the negative relationship among treatment means.The American Naturalist 07/2000; 155(6):804-813. · 4.55 Impact Factor