Life cycle and food availability indices in Notiophilus biguttatus (Coleoptera, Carabidae)

Mosquito-borne viruses continue to affect billions of people globally, posing a severe health risk and an economic burden. Aedes albopictus (Skuse), a highly invasive mosquito species, has repeatedly invaded and increased its presence, serving as a key vector of dengue virus, yellow fever virus (YFV), Zika virus (ZIKV), and Chikungunya virus (CHIKV), causing frequent outbreaks of related viral diseases. This study investigated the impact of larval diet quantity on larval duration and adult body size. The effect of adult mosquito body size on various aspects of Ae. albopictus was also examined, including blood-feeding behavior, follicular development, reproductive capacity, egg retention capacity, preoviposition period, and fecundity. These diverse characteristics all have an effect on arboviruses transmission. The changes in body size (small, medium, and large) are obtained by providing different quantities of larval diet (low, average, and high). The results indicate that the quantity of larval diet directly impacts the adult body size while inversely affecting the larval duration. Furthermore, a positive correlation exists between adult body size and wing length, implying that wing length could be a reliable indicator of adult body size and rearing conditions during the developmental stages. Large females exhibited higher numbers of follicles and greater fecundity. Moreover, a significant correlation was observed between follicle number before the first blood meal and total egg number. In contrast, increasing wing length decreased the number of blood meals, egg retention, and the preoviposition period. The tendency of small females to perform multiple feedings was greater than that of large females. Small females exhibited a higher propensity for multiple feeding activities when compared to their larger counterparts. Most medium-sized females (92.8%) deposited eggs in their ovaries, however, 7.2% retained a few. In contrast, most large females (87.4%) had complete ovary egg-laying, whereas a minority (12.6%) retained some of their eggs. About 35.2% of small females showed ovarian egg retention, while 64.8% successfully laid all their eggs. After the first blood meal, the oviposition rate was 92% for large females, 88% for medium females, and 76% for small females. About 69.86% of the follicles in large females underwent vitellogenesis. This finding suggests that small females with low energy reserves exhibited incomplete oviposition and multiple blood feedings to increase their reproductive capacity. RESEARCH HIGHLIGHTS: Add more information about arbovirus epidemics and their consequences. Aedes albopictus is a global invasive species that transmit dengue virus, CHIKV, YFV, and ZIKV. A negative correlation was observed between body size, egg retention, and multiple blood feedings in Aedes albopictus. Size of the female's body was positively correlated with fecundity, while it was negatively correlated with the preoviposition period. Size-dependent multiple blood feeding affects vector-host contact frequency.

The mechanistic basis of differences in adult body size between two closely related freshwater amphipod species (Hyalella spp.) are investigated. The study populations, Duck Lake and George Pond, are representative of two sibling species found in southeast Michigan, U.S.A that differ in adult body size and life history. An analysis of relative growth rates across size classes indicated that growth rates were similar in small size classes, but divergent at larger size classes, with higher growth rates in Hyalella from George Pond. Because the timing of the divergence coincides with the onset of reproduction in the Duck Lake population, which reaches sexual maturity at a smaller body size than individuals in the George Pond population, tradeoffs in allocation of resources between growth and reproduction probably contribute substantially to population differences in adult body size. Resource consumption rates were similar between populations in small and intermediate size classes, but large Duck Lake adults had lower consumption rates than George Pond individuals of similar size. Thus, differences in resource consumption rate may also contribute to differences in adult growth rate and body size.

The majority of animal species have complex life cycles, in which larval stages may have very different morphologies and ecologies relative to adults. Anurans (frogs) provide a particularly striking example. However, the extent to which larval and adult morphologies (e.g. body size) are correlated among species has not been broadly tested in any major group. Recent studies have suggested that larval and adult morphology are evolutionarily decoupled in frogs, but focused within families and did not compare the evolution of body sizes. Here, we test for correlated evolution of adult and larval body size across 542 species from 42 families, including most families with a tadpole stage. We find strong phylogenetic signal in larval and adult body sizes, and find that both traits are significantly and positively related across frogs. However, this relationship varies dramatically among clades, from strongly positive to weakly negative. Furthermore, rates of evolution for both variables are largely decoupled among clades. Thus, some clades have high rates of adult body-size evolution but low rates in tadpole body size (and vice versa). Overall, we show for the first time that body sizes are generally related between adult and larval stages across a major group, even as evolutionary rates of larval and adult size are largely decoupled among species and clades.

BackgroundObesity is strongly associated with inflammation and inflammatory arthritis, but most studies to date have only examined adulthood body mass index (BMI). Whether childhood obesity has a direct and long-term...

Adult body size correlates strongly with fitness, but mean body sizes frequently differ among conspecific populations. Ultimate, fitness-based explanations for these deviations in animals typically focus on community-level or physiological processes (e.g., competition, thermoregulation). However, proximate mechanisms underlying adaptive body size adjustments remain poorly understood. Adjustments in adult body size may result from shifts in growth-related life-history traits, such as the length of time to achieve adult body size (i.e., growth period) and how quickly the body increases in size (i.e., growth rate). Since insular populations often demonstrate dramatic shifts in adult body size, island populations represent a natural experiment by which to test the proximate mechanisms of size change. Here, using dental eruption patterns, we show that a dwarfed population of black-tailed deer (Odocoileus hemionus columbianus) experiences significant heterochronic shifts relative to mainland conspecifics. Namely, juvenile development slowed, such that teeth erupted ≥ 1year later, but cranial growth suggested no concurrent adjustments in skeletal growth period. Thus, slowed growth rate, shown here with teeth, combined with unchanged growth period resulted in dwarfism, consistent with ultimate predictions for insular, resource-limited populations. Therefore, selection on body size may act on life-history traits that influence body size, rather than acting on body size directly.

Body size is a key feature of organisms and varies continuously because of the effects of natural selection on the size-dependency of resource acquisition and mortality rates. This review provides a critical and synthetic overview of body size variation in insects from a predominantly macroecological (large-scale temporal and spatial) perspective. Because of the importance of understanding the proximate determinants of adult size, it commences with a brief summary of the physiological mechanisms underlying adult body size and its variation, based mostly on findings for the model species Drosophila melanogaster and Manduca sexta. Variation in nutrition and temperature have variable effects on critical weight, the interval to cessation of growth (or terminal growth period) and growth rates, so influencing final adult size. Ontogenetic and phylogenetic variation in size, compensatory growth, scaling at the intra- and interspecific levels, sexual size dimorphism, and body size optimisation are then reviewed in light of their influences on individual and species body size frequency distributions. Explicit attention is given to evolutionary trends, including gigantism, Cope's rule and the rates at which size change has taken place, and to temporal ecological trends such as variation in size with succession and size-selectivity during the invasion process. Large-scale spatial variation in size at the intraspecific, interspecific and assemblage levels is considered, with special attention being given to the mechanisms proposed to underlie clinal variation in adult body size. Finally, areas particularly in need of additional research are identified.

Simple SummaryAge and size variation in widespread amphibians are often related to latitudinal or altitudinal temperature gradients. Species with toxic skin secretions, such as the fire salamander Salamandra salamandra, are an exception to the rule because their survival rates are relatively unaffected by predation, the major source of amphibian mortality. In contrast, average adult size varies greatly among populations, but variation is unrelated to geographical gradients. This study on four neighboring fire salamander populations inhabiting the catchments of low-order streams in the upper middle Rhine Valley (Koblenz, Germany) focuses on the identification of local environmental drivers of variation in age and body size distributions. I collected 192 individuals at two localities per stream, snout–vent length measured, clipped a toe for posterior skeletochronological age determination, and released salamanders in situ again. As expected, demographic parameters were in the range of other populations with an age at maturity of 2–3 years and a maximum lifespan of 17 years, but terrestrial habitat quality accounted for 3.6% of variation among populations. Variation in adult size resulted mainly from a carry-over effect of heavy metal contamination on juvenile growth rates. In conclusion, the average adult body size is a sensitive indicator of local habitat quality.Conspecific amphibian populations may vary widely in local demography and average body size throughout their geographical range. The environmental drivers of variation may reflect geographical gradients or local habitat quality. Among fire salamander populations (Salamandra salamandra), local demography shows a limited range of variation because high concentrations of skin toxins reduce mortality from predation to a minimum, whereas average adult body size varies significantly over a wide range. This study on four neighboring populations inhabiting the catchments of low-order streams in the upper middle Rhine Valley (Koblenz, Germany) focuses on the identification of local environmental drivers of variation in age and body size. I collected 192 individuals at two localities per stream, measured snout–vent length, clipped a toe for posterior skeletochronological age determination, and released salamanders in situ again. Populations were similar in age distribution. Local habitat quality accounted for a significant proportion of demographic variability, mediated by the impact of landscape-induced mortality risk, including roads and agriculture. Still, the main effect of variation in habitat quality was on adult body size, the result of growth rates of aquatic larvae and terrestrial juveniles. Larvae exposed to non-lethal heavy metal contamination in streams developed into smaller juveniles and adults than clean-water larvae, providing evidence for carry-over effects from one stage to another. The generally small average adult size in the Rhine Valley populations compared to those in other parts of the distribution range indicates the action of a still unidentified environmental driver.

Glyptotendipes paripes larvae were reared in wells of tissue culture plates, in groups of 2, 4, 8, 16, and 32 (representing densities of about 1,300, 2,600, 5,200, 10,400, and 20,800 larvae per m2, respectively). Larval groups were supplied with one of two concentrations (low or high) of food and larvae were individually observed to evaluate the effects of density on mortality, growth, development, behavior, and adult body size. Increased larval densities resulted in higher mortality, as well as slower larval growth and development. The distribution of developmental time became flatter at higher density, with a wider range of values, or even became bimodal. This was a consequence of the most rapidly developing individuals at higher densities emerging as adults sooner than the fastest developing individuals at lower densities, although overall mean developmental time was longer at higher densities. At higher densities, growth and development of smaller larvae were slowed, based on the relative difference in body length between competitors. When larger competitors emerged as adults or died, the growth of smaller larvae may have accelerated, resulting in increased variability of developmental times. The effect of larval density on adult body size was complex, with the largest body size found at the lowest density and a second peak of adult size at high-middle densities, with smaller adult body sizes found at low-middle, and high densities. Similarly, as with developmental time, the range of body size increased with increasing density. Examined food concentrations had no effect on larval mortality, but significantly affected developmental time, growth rate, and adult body size. At higher densities, larvae spent more time gathering food and were engaged in aggressive or antagonistic behaviors.

Geographical variations in adult body size and reproductive life history traits in an invasive anuran, Discoglossus pictus

Latitudinal and elevational trends in body size are found in numerous animal taxa, with various adaptive explanations proposed. It is however debatable whether geographic trends in adult body size are accompanied by corresponding differences in juvenile growth rate (= mass gain per unit time). Respective studies have been complicated by conceptual and methodological problems related to defining and measuring this variable, particularly in organisms with discontinuous growth like arthropods. Using an original method for estimating differential (instantaneous) juvenile growth rates, we compared geographically distant European populations of six insect species in a common garden experiment. We found no among population differences in differential growth rate in any of the species. This result is in concert with concurrent increase in both adult size and developmental time towards the south. While opposite examples exist, we interpret our results as challenging the view that growth rate is a trait that readily responds to environmentally based selective pressures. Our results thus advocate the more classical view of growth rate maximisation within its physiological limits. We discuss the advantages of using differential (rather than integral) measures of growth rate in evolutionary ecological studies and evaluate the reasons for the detected latitudinal trends in life history traits.

BackgroundThe relationships between body size changes and the risk of hypertension and metabolic dysfunction-associated steatotic liver disease (MASLD) are still unclear. This study examined the independent and combined influences of child and adult body size on the risk of adulthood hypertension and MASLD.MethodsWe included 226,420 participants from the UK Biobank who were free of hypertension and liver diseases. Child-to-adult body size categories were identified based on self-reported childhood body size and measured BMI in adulthood. Cox proportional hazard regression models were applied to assess the associations between body size categories and the incidence of hypertension and MASLD. Mediation analyses to address the effect of anthropometric measures and metabolic risk factors were also performed.ResultsAfter a median follow-up of approximately 13 years, 28,662 individuals had developed hypertension (N = 27,624) and/or MASLD (N = 1,692). Low body size in childhood increased the risk of adulthood hypertension and MASLD, regardless of adult body size. Individuals with low child body size and high adult body size exhibited the highest risk for both hypertension (HR 2.01, P < 0.001) and MASLD (HR 3.28, P < 0.001). Individuals who had high child body size but average body size in adulthood had risks of the two diseases that were similar to those of persons who had an average body size consistently (all P > 0.05). Body size changes influenced hypertension through significant natural direct effects and indirect effects via anthropometric and metabolic factors, while their impact on MASLD was primarily mediated by these factors without significant direct effects.ConclusionsChildhood leanness exacerbates the risk of hypertension and MASLD in adulthood. Within the follow-up period, normal adult body size would mitigate the detrimental effects of childhood obesity. Thus, attention should be given to reinforcing weight management in children by implementing evidence-based strategies.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12889-025-24317-4.

ObjectiveTo evaluate whether body size in early life has an independent effect on risk of disease in later life or whether its influence is mediated by body size in adulthood.DesignTwo...

We documented gosling size in late summer, adult body size, and clutch size of known-age Black Brant (Branta bernicla nigricans) females nesting on the Tutakoke River colony between 1986 and 1995. During this period, the colony increased from 1,100 to >5,000 nesting pairs. Gosling mass at 30 days of age declined from 764 ± SE of 13 g and 723 ± 15 g for males and females, respectively, in the 1986 cohort, to 665 ± 18 g and 579 ± 18 g in the 1994 cohort. Gosling size was directly negatively correlated with number of Black Brant broods. We detected no trend in adult body size for individuals from these cohorts; in fact, adults from the 1992 and 1994 cohorts had the largest overall masses. Clutch size increased with age from 3.4 eggs for 2-year-old females to 4.4 eggs for 5-year-old females. Clutch size declined during the study by 0.20 (3-year-old females) to 0.45 (2-year-old females) eggs. Clutch size did not decline between the 1986 and 1990 cohorts for females that were >5 years old. Our results for clutch size and gosling size are similar to those recorded for Lesser Snow Geese (Chen caerulescens caerulescens). Our failure to detect a trend in adult body size, however, differs from the response of other geese to increasing population density. We interpret this difference in effects of density on adult size between Black Brant and other geese as an indication of stronger selection against the smallest individuals in Black Brant relative to other species of geese.

Ectothermic animals exhibit two distinct kinds of plasticity in response to temperature: Thermal performance curves (TPCs), in which an individual's performance (e.g., growth rate) varies in response to current temperature; and developmental reaction norms (DRNs), in which the trait value (e.g., adult body size or development time) of a genotype varies in response to developmental temperatures experienced over some time period during development. Here we explore patterns of genetic variation and selection on TPCs and DRNs for insects in fluctuating thermal environments. First, we describe two statistical methods for partitioning total genetic variation into variation for overall size or performance and variation in plasticity, and apply these methods to available datasets on DRNs and TPCs for insect growth and size. Our results indicate that for the datasets we considered, genetic variation in plasticity represents a larger proportion of the total genetic variation in TPCs compared to DRNs, for the available datasets. Simulations suggest that estimates of the genetic variation in plasticity are strongly affected by the number and range of temperatures considered, and by the degree of nonlinearity in the TPC or DRN. Second, we review a recent analysis of field selection studies which indicates that directional selection favoring increased overall size is common in many systems-that bigger is frequently fitter. Third, we use a recent theoretical model to examine how selection on thermal performance curves relates to environmental temperatures during selection. The model predicts that if selection acts primarily on adult size or development time, then selection on thermal performance curves for larval growth or development rates is directly related to the frequency distribution of temperatures experienced during larval development. Using data on caterpillar temperatures in the field, we show that the strength of directional selection on growth rate is predicted to be greater at the modal (most frequent) temperatures, not at the mean temperature or at temperatures at which growth rate is maximized. Our results illustrate some of the differences in genetic architecture and patterns of selection between thermal performance curves and developmental reaction norms.

Growth rate and body size at maturity are important life-history traits of interest because they represent a potential source of fitness variance within a species and provide information for understanding the nutritional condition, fecundity, and dynamics of populations. My objective here was to examine the growth rate and body size at maturity of Florida black bears Ursus americanus floridanus using body length, chest girth, and body weight measurements fitted to the nonlinear von Bertalanffy, Gompertz, and logistic size-at-age growth functions. The von Bertalanffy model had the largest Akaike weight, indicating the best fit for all measurements of both sexes. Growth models showed that females grew more slowly, with a younger age at maximum growth, faster rate at which maturity was reached, and attained significantly smaller asymptotic body length, chest girth, and weight than males. A more conservative growth strategy by females to invest available energy resources to costs of reproduction, together with intrasexual selection among males for larger body size to enhance intimidating and fighting ability to increase reproductive and survival success, are implicated as determinants of the male-biased direction and degree of sexual size dimorphism. In both sexes, the presence of human food in the diet increased the asymptotic body weight from the estimate for bears consuming a natural diet, but differences were insignificant. Females consuming human food had a slightly younger age at maximum growth and continued growth in body weight for a somewhat longer duration than did conspecifics that consumed a natural diet. In contrast, males that consumed human food had a slightly older age at maximum growth and decreased body weight growth somewhat earlier than did conspecifics consuming a natural diet. Florida black bears exhibited a larger asymptotic body size, faster growth rate, and younger age at maximum growth and maturity when compared with conspecifics in other mainland populations. Recognition of Florida black bear growth rate and adult body size provides wildlife managers a foundation for implementing measurable criteria to assess trends in population health.