Large Female Size Research Articles

The origins and drivers of sexual size dimorphism in sharks.

While sexual size dimorphism (SSD) is abundant in nature, there is huge variation in both the intensity and direction of SSD. SSD results from a combination of sexual selection for large male size, fecundity selection for large female size and ecological selection for either. In most vertebrates, it is variation in the intensity of male-male competition that primarily underlies variation in SSD. In this study, we test four hypotheses regarding the adaptive value of SSD in sharks-considering the potential for each of fecundity, sexual, ecological selection and reproductive mode as the primary driver of variation in SSD between species. We also estimate past macroevolutionary shifts in SSD direction/intensity through shark phylogeny. We were unable to find evidence of significant SSD in early sharks and hypothesise that SSD is a derived state in this clade, that has evolved independently of SSD observed in other vertebrates. Moreover, there is no significant relationship between SSD and fecundity, testes mass or oceanic depth in sharks. However, there is evidence to support previous speculation that reproductive mode is an important determinant of interspecific variation in SSD in sharks. This is significant as in most vertebrates sexual selection is thought to be the primary driver of SSD trends, with evidence for the role of fecundity selection in other clades being inconsistent at best. While the phylogenetic distribution of SSD among sharks is superficially similar to that observed in other vertebrate clades, the relative importance of selective pressures underlying its evolution appears to differ.

Sex Ratio, Sexual Dimorphism, and Wing Geometric Morphometrics in Species of Trypoxylon Latreille, 1796 (Hymenoptera: Crabronidae).

Studying the nesting biology of wasp and bee species provides valuable insights into the ecology and evolution of these insects, shedding light on their ecological significance and aiding in their conservation efforts. Trypoxylon Latreille, 1796 is a genus of spider-hunting wasps that provisions their brood with paralyzed preys. This study focuses on aspects of nesting biology of Trypoxylon (Trypargilum) species such as sex ratio, sexual dimorphism, and morphometric variation at both inter- and intraspecific levels. The secondary sex ratio (SR) exhibited variation among species and populations. Males predominantly emerged from the first brood cells and from trap nests with smaller diameters. In comparison, females showed significantly larger body mass and linear wing measurements than males. Procrustes ANOVA values for centroid size (CS) and wing shape (SH) indicated significant differences in both wing size and shape among the five analyzed Trypoxylon species. Sexual dimorphism indices (SDI) derived from centroid size were found to be similar to those obtained from linear measurements, while SDI values based on body mass were significantly higher. Nests containing a greater number of cells tended to produce a larger number of higher-quality males and females. This observation, along with the lower coefficient of variation for female body size and high heritability, suggests that this trait may be subject to natural selection. Further studies that estimate the size of parents and their respective offspring are necessary to confirm the fitness advantage associated with larger female sizes in Trypoxylon species.

Defining Patterns in Ocean Quahog (Arctica islandica) Sexual Dimorphism along the Mid-Atlantic Bight

The ocean quahog, Arctica islandica (Linnaeus 1767), is a commercially important species along the western Atlantic continental shelf. It is a long-lived species, frequently reaching ages over 200 y. Uniquely, it is one of the few bivalves to display sexual dimorphism, in that females grow to sizes larger than those of males. This phenomenon is believed to occur because males reach sexual maturity before females and, thus, have slower growth rates earlier. The growth rates of A. islandica from four sites across the Mid-Atlantic Bight, Georges Bank, Long Island (LI), and north and south of the Hudson Canyon, were measured to determine patterns in growth between males and females. Females begin to outgrow males between the ages of 5 and 15 y at sizes 50–55 mm, though this varies amongst the sites and between decades. Each of the sites is unique in some way, but three sex-dependent growth dynamics are observed. Most commonly, the two sexes diverge in size with females outpacing males in growth rates after the first 5–15 y of life. This outcome occurs at all sites and is generally the most common outcome across decades. In a few cases, female growth rates outpace the males very early in ontogeny. Such cases occur at two sites north of Hudson Canyon, both on the LI continental shelf. Most rarely, the two sexes maintain similar growth rates. This is observed for a few decades at the most southern site. In the population as a whole, these rare outcomes have limited influence on the population so that female-to-male ratio consistently increases with increasing size. This sexually dimorphic growth is not caused by protandry, nor is it compensation for a differential mortality rate between the sexes. Cases where males grow as fast as females may be just as easily indicative of a constraint on female growth as a facilitation on male growth. Egg sizes in A. islandica are larger than those of most other bivalves with planktotrophic larvae. Accordingly, another viable hypothesis is that differential growth is an adaptation to support the large egg sizes in females, where larger female size is essential to counterweigh the consequent reduced fecundity due to larger egg volume.

Evolution of sexual dimorphism in the plateau brown frog fails to obey Rensch’s rule

Rensch’s rule describes sexual size dimorphism (SSD) that decreases with increasing body size when females are larger than males and SSD that increases when males are larger than females. The plateau brown frog Rana kukunoris, a species endemic to the eastern Tibetan Plateau, exhibits female-biased size dimorphism. Using data on body size from 26 populations and age from 21 populations, we demonstrated that SSD did not increase with increasing mean female snout-vent length (SVL) when controlling for sex-specific age structure, failing to support the Rensch’s rule. Thus, we suggest that fecundity selection (favouring large female size) balances out sexual selection (favouring large male size), which results in a similar divergence between males and females body size. In addition, sex-specific age differences explained most of the variation of SSD across populations.

Seasonal variations in population dynamics of Calanus finmarchicus in relation to environmental conditions in the southwestern Norwegian Sea

A seasonal study of the life cycle and reproductive biology of the copepod Calanus finmarchicus – the dominant zooplankton species and a key link between the lower and higher trophic levels within the southwestern Norwegian Sea - is presented. C. finmarchicus reproduces, feeds and accumulates lipids during spring and summer within surface waters, which enables it to survive overwintering at depth until the following spring. An inflow of warm and saline Atlantic Water (AW) enters from the southwest and meets the cold and less saline subarctic waters (SAW) flowing from the north and west. This confluence establishes the dynamic Iceland Faroe Front. The study includes seven cruises, conducted from July 2013 to July 2014. Ascent occurred earlier and over a prolonged period in AW compared to the SAW. The peak egg production per capita occurred in April (43 eggs female−1 d−1) and May (13 eggs female−1 d−1) in SAW and AW, respectively. The higher productivity in SAW can be explained by larger female size, increased lipid content and better feeding conditions. The increased egg production rates in May in AW were not reflected in an increased abundance of young copepodite stages in June, potentially due to a decoupling between early ascent and the late onset of the bloom. Descent, largely comprised by the pre-adult stages, to overwintering depths was already initiated in June in both regions. This coincides with increased lipid content, being significantly higher at depth compared to the surface in late summer. A smaller portion of individuals remained within the upper layers to spawn a second generation in August in both regions, increasing the abundance and biomass. The reproductive phenology and stage development of C. finmarchicus likely influence feeding and competition between herring and mackerel and the duration of their stay in Faroese waters.

Spawning season, recruitment, and growth of the freshwater prawn Macrobrachium lamarrei (H. Milne-Edwards, 1837) in a perennial wetland, northeastern Bangladesh

Abstract Spawning season, recruitment, and growth of the freshwater prawn Macrobrachium lamarrei were studied in a perennial wetland, northeastern Bangladesh during October 2016 to September 2017. Spawning season was estimated based on the monthly variations of percent ovigerous females. Recruitment and growth were estimated using the time series of the length-frequency distributions. We compared the von Bertalanffy growth function (VBGF) and the Pauly and Gaschutz growth function (PGGF) to identify any seasonal oscillation in growth rate. Ovigerous females occurred almost throughout the year, indicating a prolonged spawning season with two peaks between March-April (minor peak) and June-September (major peak). Both males and females with modal size ~ 8.0 mm carapace length first recruited in October, which synchronized with the major peak spawning season. There was seasonality in growth rate; hence, PGGF was adopted as the best-fitting model to describe the growth of both sexes. The estimated equations were Lt = 17.86 (1- exp [-2.432 (t/12 - 0.072) - (1.766/2π) sin {2π (t/12 - 0.982)}] for males and Lt = 23.18 (1- exp [-1.342 (t/12 + 0.106) - (0.388/2π) sin {2π (t/12 - 0.209)}] for females. Sexual dimorphism was found with larger size in females than males. Longevity was estimated to be ~ 14 months for both sexes. These findings can be useful to formulate management measures for this prawn.

Size and sex bias in air-exposure behavior during low tide of the intertidal hermit crab Clibanarius virescens (Krauss, 1843) (Decapoda: Anomura: Diogenidae)

Abstract Many species of the hermit crab Clibanarius (Diogenidae) live on rocky shores of tropical and warm temperate regions. Some of these species are known to climb out from tidal pools onto rock surfaces exposed to air during low tide. The ecological significance of this behavior, however, remains unclear. We investigated the differences between air-exposed and non-air-exposed Clibanarius virescens (Krauss, 1843) in relation to their body size, sex, and infestation by three species of parasitic bopyrid isopods. Our generalized additive model (GAM) analyses showed a significant effect of the “smoothing factor” of the interaction between body size and sex for the occurrences of the “air-exposure behavior.” The presence of the ectoparasitic isopods did not affect the air-exposure behavior. Females of C. virescens showed a more distinct trend than in males, whereas air-exposure in both sexes had a peak in approximately 3.0–4.0 mm shield size (comparatively larger size in females, and middle-size in males) and decreased after this size range. Intraspecific and/or interspecific competition for shells may be intense in hermit crabs of this size range because of size overlap, and the individuals that carry suitable shells may avoid such competition by actively escaping from tide pools at low tide.

Complex and Diverse Drivers of Parasite Loads in a Cosmopolitan Insect

The goal of parasite epidemiologists is to understand the factors that determine host infection levels. Potential infection determinants exist at many scales, including spatial and temporal environmental variation, among-host differences, and interactions between symbionts infecting the same host. All of these factors can impact levels of parasitism, but frequently only a subset is considered in any host-parasite system. We examined several potential determinants of pinworm infection in wild Australian cockroaches (Periplaneta australasiae) from multiple biological scales: (1) habitat; (2) season; (3) cockroach body size, developmental stage, and sex; and (4) interactions between 2 pinworm species (Leidynema appendiculata and Thelastoma sp.). Over 1 yr, we collected 239 cockroaches from 2 separate rooms in an Illinois greenhouse. We used generalized linear mixed-effects models (GLMMs) to evaluate simultaneously the influence of these factors on pinworm abundance, and nearly all had significant effects. Overall, the abundance of L. appendiculata was greater than Thelastoma sp., but the relative abundance of the 2 species was reversed in each room (i.e., a taxon × habitat effect). Abundance varied over 4 trapping seasons and increased with cockroach size. Adult cockroaches had more pinworms than nymphs, and there was also a significant taxon × stage effect: adult cockroaches had fewer pinworms than expected for their larger size, and this reduction was greater in Thelastoma sp. than in L. appendiculata. Cockroach sex had no effect on infection. Although females had more worms than males, this difference could be explained by the larger size of females. Finally, after controlling for all other potential determinants of infection, we found a strong negative association between Thelastoma sp. and L. appendiculata; cockroaches tended to be infected with either 1 pinworm species or the other. Our work underscores the importance of measuring potential determinants of infection from as many scales as possible. Such approaches are necessary to unravel the complexities of host-parasite interactions.

The alien slipper limpet Crepipatella dilatata (Lamarck, 1819) in northern Spain: A multidisciplinary approach to its taxonomic identification and invasive biology.

The slipper limpet Crepipatella dilatata, native to Chile and Argentina, was introduced in Spain in 2005. The species was thought to inhabit the region of Rias Bajas, yet recently, putative C. dilatata populations have been documented on the coast of north-central Spain and in the Ebro Delta of the Spanish Mediterranean. Here we undertook a multidisciplinary approach to study the invasion biology of this species. Specifically, two geographically distant populations, one being a successfully established population from O Grove and the other a declining population from Gijon, were studied over the course of four years. Analyses of morphological and developmental traits as well as genetic information confirmed the presence of C. dilatata in these sites. The results revealed polymorphism in anatomical traits and shell shape. Shell shape polymorphism was unevenly distributed among sites and among sexes. Males were monomorphic, while females were polymorphic. Of the female morphotypes encountered, one was absent in the declining population from Gijón. Size at first female maturation and female size were greater in the declining population than in the established population. Reproductive success varied seasonally but not spatially among populations. In the established population, gregariousness was significantly greater; the size when sex changes was found to be plastic and socially controlled. The sex ratio of the declining population was female biased while in the established population the sex ratio changed during the study period from being balanced to being female biased. This change in sex ratio was probably due to higher male mortality. Molecular analyses pointed to the localities of Corral Bay in southern Chile and Puerto Madryn in southern Argentina as potential population sources. The intercontinental import of fresh mussels cultivated in Chilean farms is a likely source of this mussel in Spain. Comparison with available data of native populations of C. dilatata strongly indicate that ecophenotypic plasticity, socially controlled sex change, high gregariousness, increased nurse egg supply to viable larvae during the encapsulated developmental period, later maturation and larger female sizes altogether enhance establishment success of this non-indigenous species. Human-mediated factors like the intraregional mussel trade and transplantation are also likely secondary dispersal mechanisms favouring the spread of this organism.

Is the Pelvis Sexually Dimorphic in Turtles?

Variation in the pelvis is intrinsically linked to life history evolution. This is perhaps best exemplified by sexually dimorphic pelvic variation in bipedal primates. Yet, whether this trend is applicable to other taxa is unclear. Using turtle anatomy as a model, I tested the hypothesis that the pelvis is also sexually dimorphic in egg-laying tetrapods. I sampled a natural turtle population with female-biased sexual size dimorphism (i.e., larger females). I show that the area of the egg canal (pelvic aperture) is greater in females. Morphological differences between sexes were predicted by body size, such that skeletal shape deformation of the female ilium increased proportionally with pelvic aperture area. These results suggest that sexual pelvic dimorphism might be indirectly maintained by selection for large female size, consistent with the pelvic constraint hypothesis in reptiles. However, subsampling of similarly sized individuals revealed that pelvic aperture area and shape may vary in disproportion to body size. Comparisons of pelvic ontogenetic trajectories across multiple lineages are needed to clarify the occurrence of sexual pelvic dimorphism in turtles and other egg-laying tetrapods. My findings provide impetus to further explore how sex-specific functional demands influence the architecture of the pelvic girdle. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.

How to become larger: ontogenetic basis of among‐population size differences in a moth

AbstractEvolutionary studies on animal body size have primarily focussed on selective pressures operating during the adult life. In contrast, ontogenetic pathways leading to differently sized adults have received less attention. In the present study, based on a common garden experiment, we report considerable genetic differences in body size among European populations of Ematurga atomaria (L.) (Lepidoptera: Geometridae). In terms of body mass, the moths from a southern (Georgian) population are twice as large as their northern (Estonian) conspecifics. Detailed monitoring of larval growth schedules revealed that the size difference arises through a longer development period of the Georgian larvae, with no difference in the number of instars. Differential (instantaneous) growth rates of the larvae do not differ between the populations. Eggs and newly hatched larvae are larger in the Georgian population but the difference vanishes in the second instar. The larger size of the Georgian moths is regained through higher relative mass increments during each of the three final instars. Such gradual ‘accumulation of the difference’ confirms the idea about constraints on substantial evolutionary changes in growth patterns within a single instar. The larger Georgian moths were found to be considerably more fecund which implies a strong selection for large female size. It remains unclear which counteracting selective pressures have favored the smaller size of Estonian conspecifics. As the associated difference in egg size appears not to be carried over to larger larval size, the adaptive value of larger eggs is not likely in contributing to the prospective large adult size. The larger eggs of the Georgian population should have an adaptive value per se, or represent a mechanistic consequence of larger maternal body size.

Variation in skull size and shape of two snake species (Natrix natrix and Natrix tessellata)

We examined morphological differences in cranium size and shape between closely related snake species, Natrix natrix and Natrix tessellata (Natricinae, Colubroidea), as well as variation within species. These two snake species have similar ecology and habitat preferences but differ in feeding strategies. Our hypothesis was that divergence in size and shape of cranial elements between species depends on their functional role and anatomical relationships. To analyse complex, kinetic crania, we applied computed microtomography and 3D geometric morphometrics. We analysed size and shape of six cranial elements separately. We selected two “non-trophic” structures (akinetic braincase and mobile nasals) and four movable “trophic” skeletal elements (maxillae, quadrates, pterygoids and compound bones) which are involved in prey capture and swallowing. Our results showed that N. natrix and N. tessellata significantly differ in size and shape of all analysed cranial elements. In both species, cranium is significantly larger in females than in males. To account for possible differences in shape due to differences in size, we estimated allometric and non-allometric component of shape variation. For all elements, except nasals, allometry accounted for a significant proportion of the variance in shape. The analysis of non-allometric component of shape variation revealed significant dimorphism in shape of the braincase and maxilla between N. tessellata females and males, and marginally significant sexual dimorphism in shape of maxilla in N. natrix. These results indicated that sexual dimorphism in skull shape is species specific and not entirely caused by selection for larger size in females.

Absence of Mate Choice and Postcopulatory Benefits in a Species with Extreme Sexual Size Dimorphism

Most hypotheses related to the evolution of female-biased extreme sexual size dimorphism (SSD) attribute the differences in the size of each sex to selection for reproduction, either through selection for increased female fecundity or selection for male increased mobility and faster development. Very few studies, however, have tested for direct fitness benefits associated with the latter – small male size. Mecaphesa celer is a crab spider with extreme SSD, whose males are less than half the size of females and often weigh 10 times less. Here, we test the hypotheses that larger size in females and smaller size in males are sexually selected through differential pre- and postcopulatory reproductive benefits. To do so, we tested the following predictions: matings between small males and large females are more likely to occur due to mate choice; females mated to small males are less likely to accept second copulation attempts; and matings between small males and large females will result in larger clutches of longer-lived offspring. Following staged mating trials in the laboratory, we found no support for any of our predictions, suggesting that SSD in M. celer may not be driven by pre- or post-reproductive fitness benefits to small males.

Reproductive life history of Heterandria bimaculata (Heckel, 1848) (Poeciliinae: Poeciliidae) in the Honduran interior highlands: trait variation along an elevational gradient

Abstract This study examined reproductive traits and growth rates of Heterandria bimaculata (Poeciliidae) in Cusuco National Park (CNP), a cloud forest reserve in northern Honduras, Central America. In CNP, H. bimaculata occurs in the absence of other fish species and major invertebrate predators along an approximately 1000 m elevation gradient. This allowed for the examination of trait variation along the gradient without the confounding effects of interspecific interactions or habitat patchiness. Heterandria bimaculata exhibited traits characteristic of a low-predation environment: balanced sex ratio, slow growth, late maturity and large female size. Females produced more, smaller eggs from upstream to downstream, but overall reproductive allocation remained constant along the gradient. Maximum male length and annual growth rates increased from upstream to downstream, but female growth showed no trend. The patterns of growth and reproductive allocation tradeoff are consistent with predicted response to a longitudinally-increasing productivity gradient in which food resources become more abundant downstream. Macrobrachium and Bellastoma could have caused some predation, but were sparse and patchily distributed. Fish density remained fairly constant among elevations; if food resources were limiting in upstream habitats, per-capita resource availability would be lower and density-dependent competition would drive selection for larger but fewer, more competitive offspring. Future work should quantify longitudinal changes in productivity and conduct experiments to decouple the effects of stream order and fish density dependence.

Sexual size dimorphism in the viviparous caecilian amphibian Geotrypetes seraphini seraphini (Gymnophiona: Dermophiidae) including an updated overview of sexual dimorphism in caecilian amphibians

Sexual size dimorphism (SSD) describing intersexual size differences of a given taxon is a widespread phenomenon in the animal kingdom. SSD plays a significant role in understanding life history and mating system evolution. The snakelike morphology of limbless caecilian amphibians lacking obvious secondary sexual characters (in contrast to frogs and salamanders) impedes an accurate comparison between sexes.Here, the phylogenetically derived teresomatan and viviparous caecilianGeotrypetes seraphini seraphiniwas analysed for patterns of sexual dimorphism. In terms of body size females were the larger sex, but when body length was adjusted male-biased intersexual differences in cloacal shape appeared. The larger female size is likely explained by fecundity selection as clutch size was positively correlated to female body length. Unexpectedly a cryptic, ontogeny related variation of the nuchal collars was found. An overview of SSD in caecilians including data for 27 species of nine out of ten existing families revealed a quite high number of taxa showing sexually dimorphic head size dimensions exclusively present among phylogenetically derived teresomatan caecilians. Still further research including insights into the behavioural ecology and molecular ecology of mating systems is warranted to better understand the evolution of sexual size dimorphism of caecilian amphibians.

Large‐scale variation of size‐ and age‐related life‐history traits in the common frog: a sensitive test case for macroecological rules

AbstractThe potential causes underlying geographical variation of 12 age‐ and size‐related life‐history traits were studied in the common frog Rana temporaria. The meta‐analysis was based on own field data obtained in the Austrian Alps and additionally on published studies on 35 populations covering the whole range of latitudinal, longitudinal and altitudinal distribution. This extensive dataset allowed for co‐variance analyses evaluating the statistical support for five hypotheses on large‐scale trait variation derived from general macroecological rules. Contrary to Bergmann's rule, adult frogs' body size variation was unrelated to latitude (and altitude), but co‐varied with age as expected for a species that grows indeterminately. Unlike the prediction of Rensch's rule, the slight female‐biased sexual size dimorphism (SSD) did not differ significantly among populations with small and large average female size. SSD increased with altitude, but did not co‐vary with latitude, longitude and age, disagreeing with the predictions of the differential‐plasticity hypothesis. Common frogs at higher altitudes and latitudes reached reproductive maturity at significantly older ages and enjoyed an increased longevity as well. However, potential reproductive lifespan increased significantly only with altitude, compensating for the smaller clutches relative to body size in alpine populations. In conclusion, body size variation of common frogs does not actually mirror geographical gradients, but differences in age, a factor unconsidered in Bergmann's and Rensch's rules. Large‐scale environmental gradients are therefore good predictors of age‐related traits. Combining the local co‐variation of the single traits age, body size, clutch size and reproductive lifespan to calculate the resulting female lifetime fecundity (FLF), surprisingly little variation of the derived trait FLF is observed across the geographical range of the common frog. The ultimate cause of variation in age‐ and size‐related life‐history traits seems to be the selection for an optimal FLF.

НОВЫЙ ВИД MICROVALGUS KRAATZ ИЗ ВЬЕТНАМА (COLEOPTERA, SCARABAEIDAE, VALGINAE)

Microvalgus (Paediovalgus) iners sp. n. collected in the southern parts of central Vietnam (Dalat Mts.) at altitudes of 750-800 m is described. It differs from other species of the genus in strongly asymmetric parameres in males (see figs. 2, 3) and in larger size of females (3.5-4.8 mm). These characters separate the new species from any other species having the phallobase with long spine-like anterior processes.

Mating system and reproductive success in the Siberian flying squirrel

Mating systems and factors affecting reproductive success are much studied especially for mammals that are large bodied, have marked sexual size dimorphisms, and have a female-defense mating system. For species that deviate from these patterns, we need more information on mating systems and reproductive success. Here, we study mating system and factors related to reproductive success in a solitary rodent, the Siberian flying squirrel (Pteromys volans). In contrast to most other mammals, males are not larger than females in flying squirrels. Similarly to most mammalian species, we observed multimale paternity within litters and reproductive success of males being positively related to body mass. Variation in reproductive success was clearly higher for males than for females, although remained lower than observed in species with highly male-biased sexual size dimorphism. Female flying squirrels lived in nonoverlapping home ranges and reproductive success was positively related to body mass, in line with earlier predictions for large female size in mammals.

Identification of two novel female-specific DNA sequences in half-smooth tongue sole, Cynoglossus semilaevis

Half-smooth tongue sole (Cynoglossus semilaevis) is a kind of cultured teleost fish with larger size of females than males. In order to produce all-female progeny, it is necessary to distinguish the genetic females and males precisely. In this study, a W chromosome library, which had been constructed by laser microdissection of W chromosomes, was screened. Among four hundreds and twelve pairs of designed PCR primers, two pairs (W045 and W131) could produce female-specific fragments in fifty individuals. To verify the primers and optimize the method, another one hundred individuals were tested by multiplex PCR with both W045 and a pair of positive control primers. Furthermore, two sex-reversed individuals were also identified correctly. Fluorescent in situ hybridization (FISH) further confirmed that fragments form W045 and W131 primers only localized to the W chromosome in female individuals, and the FISH technique with the two female-specific fragments could help to isolate super-female individuals. The identification of two novel female-specific DNA sequences and the techniques used here may be applied to distinguish the genetic gender of half-smooth tongue sole precisely. Besides, these also help us to obtain a better understanding of fish sex determination.

Relationship of larval desiccation to Anopheles gambiae Giles and An. arabiensis Patton survival

Relationship of larval desiccation to Anopheles gambiae Giles and An. arabiensis Patton survival