Topic
Fecundity
About: Fecundity is a research topic. Over the lifetime, 9433 publications have been published within this topic receiving 226923 citations.
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TL;DR: It is concluded that host plant quality affects the fecundity of herbivorous insects at both the individual and the population scale.
Abstract: Host plant quality is a key determinant of the fecundity of herbivorous insects. Components of host plant quality (such as carbon, nitrogen, and defensive metabolites) directly affect potential and achieved herbivore fecundity. The responses of insect herbivores to changes in host plant quality vary within and between feeding guilds. Host plant quality also affects insect reproductive strategies: Egg size and quality, the allocation of resources to eggs, and the choice of oviposition sites may all be influenced by plant quality, as may egg or embryo resorption on poor-quality hosts. Many insect herbivores change the quality of their host plants, affecting both inter- and intraspecific interactions. Higher-trophic level interactions, such as the performance of predators and parasitoids, may also be affected by host plant quality. We conclude that host plant quality affects the fecundity of herbivorous insects at both the individual and the population scale.
1,962 citations
TL;DR: The common slope of the fecundity/size relationship is close to 1 and this indicates that female size is a principal constraint on insect potential FECundity.
Abstract: The relationship between intra-specific variation in female body size and potential fecundity was investigated using the published literature on 57 oviparous species of Coleoptera, Diptera, Ephemeroptera, Heteroptera, Homoptera, Hymenoptera, Lepidoptera, and Trichoptera, and 11 species of larviparous Aphidina and Diptera. Female body sizes were converted to dry body weight. Variation in body weight and fecundity was expressed as percentage deviation from the median values. The increase in fecundity with body weight was similar in most taxa, with only a few important exceptions. The common regression for oviparous and larviparous species predicts a 0.95% increase in median fecundity for each 1% increase in dry body weight. The number of ovarioles (in 10 species of Coleoptera, Diptera, Hymenoptera and Orthoptera) also increased with body weight. The general relationship predicted a 0.81% increase in ovariole number for each 1% increase in dry body weight. The slope of ovariole number versus weight relationship was greater in species with many ovarioles than in species with few. The common slope of the fecundity/size relationship is close to 1 and this indicates that female size is a principal constraint on insect potential fecundity.
1,504 citations
TL;DR: Examination of variation and covariation of life history traits of 123 North American Passeriformes and Piciformes in relation to nest sites, nest predation, and foraging sites found that number of broods was much more strongly correlated with annual fecundity and adult survival among species than was clutch size, suggesting that clutch size may not be the primary fecundation trait on which selection is acting.
Abstract: Food limitation is generally thought to underlie much of the variation in life history traits of birds. I examined variation and covariation of life history traits of 123 North American Passeriformes and Piciformes in relation to nest sites, nest predation, and foraging sites to examine the possible roles of these ecological factors in life history evolution of birds. Annual fecundity was strongly inversely related to adult survivaI, even when phylogenetic effects were controlled. Only a little of the variation in fecundity and survival was related to foraging sites, whereas these traits varied strongly among nest sites. Interspecific differences in nest predation were correlated with much of the variation in life history traits among nest sites, although energy trade-offs with covarying traits also may account for some variation. For example, increased nest predation is associated with a shortened nestling period and both are associated with more broods per year, but number of broods is inversely correlated with clutch size, possibly due to an energy trade-off. Number of broods was much more strongly correlated with annual fecundity and adult survival among species than was clutch size, suggesting that clutch size may not be the primary fecundity trait on which selection is acting. Ultimately, food limitation may cause trade-offs between annual fecundity and adult survival, but differences among species in tecundity and adult survival may not be explained by differences in food abundance and instead represent differing tactics for partitioning similar levels of food limitation. Variation in fecundity and adult survival is more clearly organized by nest sites and more closely correlated with nest predation; species that use nest sites with greater nest predation have shorter nestling periods and more broods, yielding higher fecundity, which in turn is associated with reduced adult survival. Fecundity also varied with migratory tendencies; short-distance migrants had more broods and greater fecundity than did neotropical migrants and residents using similar nest sites. HowevEr, migratory tendencies and habitat use were confounded, making separation of these two effects difficult. Nonetheless, the conventional view that neotropical migrants have fewer broods than residents was not supported when nest site effects were controlled
1,411 citations
TL;DR: Based on the asymptotic population growth rate l, calculated from a projection matrix model as a descriptor of the population dynamics, published data of 49 species of birds are analyzed to determine how l is influenced by variation in different demographic traits.
Abstract: A central goal in ecology is to predict population dynamics from demographic information. Based on the asymptotic population growth rate l, calculated from a projection matrix model as a descriptor of the population dynamics, we analyze published data of 49 species of birds to determine how l is influenced by variation in different demographic traits. Across species, the mean elasticity of the adult survival rate was significantly larger than the mean elasticity of the fecundity rate. The contribution of the fecundity rate to the population growth rate increased with increasing clutch size and decreasing adult survival rate, while the greatest contribution of adult survival rate occurred among long-lived species that matured late and laid few eggs. This represents a continuum from ''highly reproductive species'' at one end to ''survivor species'' at the other end. In addition, a high contribution of adult survival rate was found in some relatively long-lived species with early age at maturity (and a large clutch size) which was assumed to represent a bet-hedging strategy, i.e., producing a large number of offspring in some occasional good years. In a retrospective analysis, interspecific differences in the effects of actual temporal variation in adult survival rate and fecundity rate on the variability of l were analyzed. These effects are expected to be large when the variance or the sensitivity of the trait is large. Because there was a negative relationship among species, both for the adult survival rate and the fecundity rate between the variability and the sensitivity of the trait, contribution of a trait to the variance in l decreased with sensitivity. Similarly, within species, less temporal variation was found in traits with high elasticities than in traits with less contribution to l. In some species, covariance among matrix elements also influenced the contribution of a demographic trait to l. Monitoring schemes of bird demography should be designed in such a way that temporal variances and covariances among demographic traits can be estimated. Further- more, it is important in such schemes to include data from a combination of traits that either have large sensitivities or high temporal variation.
1,172 citations
TL;DR: It is suggested that an 'optimum' thermal regime exists where adult size and fecundity are maximized; temperature regimes warmer or cooler than the "optimum'' result in small and less fecund adults.
Abstract: Adult body size and fecundity of several species of hemimetabolous aquatic insects were shown to depend largely on thermal conditions during larval growth We suggest that an "optimum" thermal regime exists where adult size and fecundity are maximized; temperature regimes warmer or cooler than the "optimum'' result in small and less fecund adults Two hypotheses concerning river water temperatures and size variation of adult insects are described First, maximum adult size reflects an equilibrium between several developmental processes that appear highly temperature dependent, viz, (i) the rate and duration of larval growth, and (ii) the specific time in larval development that adult structures begin maturing and the rate of this maturation process Second, a species distribution both locally within drainage systems and over a large geographic area is limited, in part, by lowered fecundity as adult size gradually diminishes in streams of increasingly cold or warm temperature cycles The importance of riv
787 citations