Sexual differences in weight loss upon eclosion are related to life history strategy in Lepidoptera (original) (raw)
Related papers
Physiological variation in insects: large-scale patterns and their implications
2002
In this paper we demonstrate how broad scale comparative physiology has an important role to play in informing a variety of assumptions made in macroecology. We do so by examining large-scale geographic variation in insect development, thermal tolerance and metabolic rate. From these studies, and those from the literature on insect water loss and thermoregulation, we show that there is often a bias to the geographic extent of available empirical data. Studies of cold hardiness are most usually undertaken at high latitudes, while investigations of upper thermal tolerances and water loss are most common in warm arid regions. Likewise, we demonstrate that much variation in insect physiological tolerances is partitioned at higher taxonomic levels, which has important implications for comparative physiology. Intriguingly, data on the full range of variables we review are available for only three species. We also show that, despite its importance, body size is regularly reported in only some kinds of investigations (metabolic rate, water loss rate), whereas in others (upper lethal temperature, cold hardiness, development) this variable is often ignored. In short, although large-scale comparative physiology can contribute considerable understanding to both physiology and ecology, there is much that remains to be done.
Frontiers in Ecology and Evolution, 2014
Chemical communication in insects' sexual interactions is well-known to involve olfaction of volatile compounds called sex pheromones. In theory, sexual chemical communication may also involve chemicals with low or no volatility exchanged during precopulatory gustatory contacts. Yet, knowledge on this latter type of chemicals is so far mostly restricted to the Drosophila fly model. Here we provide the most comprehensive characterization to date of the cuticular chemical profile, including both volatile and non-volatile compounds, of a model butterfly, Bicyclus anynana. First, we characterized the body distribution of 103 cuticular lipids, mostly alkanes and methyl-branched alkanes, by gas chromatography coupled to mass spectrometry (GC-MS). Second, we developed a multivariate statistical approach to cope with such complex chemical profiles and showed that variation in the presence or abundance of a subset of the cuticular lipids indicated body parts, and traits involved in B. anynana mate choice, namely sex and age. Third, we identified the chemical structure of the 20 most indicative compounds, which were on average more abundant (1346.4 ± 1994.6 ng; mean ± SD) than other, likely less indicative, compounds (225.9 ± 507.2 ng; mean ± SD). Fourth, we showed that wings and legs displayed most of the chemical information found on the entire body of the butterflies. Fifth, we showed that non-random gustatory contacts occurred between specific male and female body parts during courtship. The body parts mostly touched by the conspecific displayed the largest between-sex differentiation in cuticular composition. Altogether, the large diversity of cuticular lipids in B. anynana, which exceeds the one of Drosophila flies, and its non-random distribution and evaluation across individuals, together suggest that gustatory information is likely exchanged during sexual interactions in Lepidoptera.
Abdomen Size, Body Size and the Reproductive Effort of Insects
Oikos, 1989
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . Wiley and Nordic Society Oikos are collaborating with JSTOR to digitize, preserve and extend access to Oikos. . 1989. Abdomen size, body size and the reproductive effort of insects. -Oikos 56: 209-214.
1 Insect metabolic rates are highly variable and are affected by acute environmental and behavioral, developmental, and evolutionary factors. 2 The effects of temperature on insect metabolic rates depend on their behavior, life-history stage, morphology, and size. In many cases, inactive insect metabolic rates increase with temperature in a manner consistent with the assumptions of the metabolic theory of ecology (MTE), but exceptions include insects that are flying, endothermic, or behaviorally thermoregulating. In these cases metabolic rates may remain constant or decrease with increasing temperature. 3 Insect metabolic rates are not generally constrained by oxygen limitation. 4 The metabolic rates for behaviorally active insects may be elevated up to 30 times greater than their standard resting metabolic rates, an aerobic scope greater than the comparable range found among similarly sized vertebrates. 5 Nutritional state can have dramatic influences on insect metabolic rates, ranging from extreme diapause in response to starvation to nearly 10-fold increases in metabolic rate following feeding. 6 Metabolic rate correlates with insect body size both intra- and interspecifically. The interspecific slope is ¾, as predicted by MTE. Individual insects as well as eusocial insect colonies share common hypometric scaling exponents, but there is extensive variation in the metabolic elevation (i.e., scaling intercept or normalization constant) of these allometric relationships. While some of this variation may be related to methodology and behavioral variation, it is likely that these patterns may reflect previously unrecognized evolutionary differences in physiology and life history. 7 Future extensions of MTE should include physiological, behavioral, and evolutionary mechanisms. Future developments of MTE have great potential to investigate a number of areas in which further research is in highly needed including the evolution of insect endothermy, body size, eusociality, and metabolic symmorphosis.
The Ontogeny of Sexual Size Dimorphism of a Moth: When Do Males and Females Grow Apart?
PLoS ONE, 2014
Sexual dimorphism in body size (sexual size dimorphism) is common in many species. The sources of selection that generate the independent evolution of adult male and female size have been investigated extensively by evolutionary biologists, but how and when females and males grow apart during ontogeny is poorly understood. Here we use the hawkmoth, Manduca sexta, to examine when sexual size dimorphism arises by measuring body mass every day during development. We further investigated whether environmental variables influence the ontogeny of sexual size dimorphism by raising moths on three different diet qualities (poor, medium and high). We found that size dimorphism arose during early larval development on the highest quality food treatment but it arose late in larval development when raised on the medium quality food. This female-biased dimorphism (females larger) increased substantially from the pupal-to-adult stage in both treatments, a pattern that appears to be common in Lepidopterans. Although dimorphism appeared in a few stages when individuals were raised on the poorest quality diet, it did not persist such that male and female adults were the same size. This demonstrates that the environmental conditions that insects are raised in can affect the growth trajectories of males and females differently and thus when dimorphism arises or disappears during development. We conclude that the development of sexual size dimorphism in M. sexta occurs during larval development and continues to accumulate during the pupal/adult stages, and that environmental variables such as diet quality can influence patterns of dimorphism in adults.