Intraspecific correlations among morphology, performance and habitat use within a green anole lizard (Anolis carolinensis) population

We examined habitat use, morphology, jumping and clinging ability for 403 juvenile, female and male green anole lizards, Anolis carolinensis, in a population in south‐eastern Louisiana. We sought to answer three questions: (1) Do age/sex classes differ in habitat use, morphology and performance ability? (2) Do habitat use, morphology and performance correlate among all individuals across three age/sex classes (juveniles, females and males)? (3) Do juveniles compensate for their poor absolute performance capacities by being better performers on a relative scale? The three age/sex classes were found to differ significantly in size‐adjusted morphology, habitat use and size‐adjusted performance capacity. Juveniles tended to occupy perches which were closer together than those of adult males and females. The distal elements of the hindlimb (femur, tibia) were significantly longer in males than in females and juveniles, while females were more stocky than males and juveniles. The only significant overall ecomorphological relationship detected was between the lengths of the distal hindlimb elements and maximum jump acceleration. Our hypothesis that juveniles should be better performers (relative to size) compared to adults was disproved, as adult females were always the best performers relative to size. Our analysis of a mainland anole population presents a different view of population structure compared to similar studies involving Caribbean Anolis lizards, which show more ecological differentiation among age/sex classes, and also show that juveniles are relatively good performers. © 2005 The Linnean Society of London, Biological Journal of the Linnean Society, 2005, 85 , 211–221.     

Insights of the life history in the porcellanid crab Petrolisthes armatus (Gibbes, 1850) (Crustacea: Anomura: Porcellanidae) from the Southwestern Atlantic coast

Petrolisthes armatus (Gibbes, 1850) life history was evaluated based on growth and reproduction. Specimens were captured at Ubatuba (Brazil), identified, sexed and measured: carapace (CL, length; CW, width), larger cheliped propodus (PL, length; PW, width; and PH, height), and 2th and 5th abdominal somite (AW₂ and AW₅, width). Relative growth was studied using CL as independent variable and its relation with other variables (dependents), to estimate puberty size and morphological maturity. Fecundity was represented by number of eggs vs. body size CL, with a better fit using a power function. Considering the 257 specimens analyzed, males were larger than females, and the overall sex ratio was 1:1, with some differences among size classes. Maturity (puberty size) was revealed by: AW₂ × CL (males: 8.6 mm CL; females: 7.6 mm CL); and AW₅ × CL (7.1 and 7.6 mm CL, respectively). Reproduction was continuous, but more intense in rainy season and recruitment occurring in dry season. Fecundity of this species was 228 ± 163 eggs, with better fit by a power function (R² = 0.72). Maturity size and growth differed when a pristine area (Ubatuba) was compared with a polluted area (São Sebastião), in the same Brazilian area (São Paulo State).     

Population structure,relative growth and morphological sexual maturity of the snapping shrimp Alpheus brasileiro Anker, 2012 (Caridea: Alpheidae) from the south-eastern coast of Brazil

The present study investigated the population structure of the snapping shrimp Alpheus brasileiro. We tested the hypotheses that the sex ratio of the population differs from the expected 1:1 and that the growth pattern differs between adults and juveniles and between sexes. Reproductive period, juvenile recruitment and morphological sexual maturity were estimated. Samples were collected in two periods. The first sampling occurred bimonthly from March 2013 to January 2014. The second sampling occurred monthly from April 2015 to March 2016. The population structure was determined based on the size-frequency distribution of different demographic categories. To analyse the relative growth, we measured the second pleuron length, major cheliped propodus length, major cheliped propodus width, major cheliped propodus height, appendix interna length, appendix masculina length. The results showed that the sex ratio did not differ from 1:1 (male:female). Reproduction and juvenile recruitment were continuous throughout the study period. The analysis of relative growth confirmed the hypothesis that males and females, and juveniles and adults, have different growth patterns, indicating distinct strategies of energy allocation. The estimated carapace length at the onset of morphological sexual maturity was 4.9?mm in males and 4.7?mm in females. The results obtained in this study are probably related to the monogamous social behaviour of A. brasileiro. Monogamy can influence demographic parameters such as sex ratio and the size at which males and females reach morphological sexual maturity.     

Age, growth and reproductive characteristics of chub, Leuciscus cephalus (L., 1758) in the İkizcetepeler dam lake (Balikesir), Turkey

In this study, the population structure, growth and reproduction characteristics of 414 chub (Leuciscus cephalus L., 1758) from the ?kizcetepeler dam lake were investigated monthly between January and December 2000. Age groups ranged between I and VI for this species in the reservoir, with the second and third year‐classes dominating. Sex ratio was 1 : 1.4 (M : F), corresponding to 58.4% males and 41.6% females. Females attained greater size and age than males. The largest female captured was 24.8 cm FL, the largest male was 24.1 cm FL, both age VI. The von Bertalanffy growth equations and length–weight relationships were found as: L_t = 28.89[1 ?e^{?0.224(t+1.55)}] for females, L_t = 26.71[1 ? e^{?0.259(t+1.55)}] for males; W_t = 347.386[1?e^{?0.224h (t+1.55)}]^2.86 for females, W_t =286.48[1?e^{?0.259 (t+1.55)}]^2.92 for males; W = 0.0227 × L^2.87 for females and W = 0.0194 × L^2.92 for males. Significant statistical differences in condition factors between age classes and sexes were not found (P > 0.05, t‐test). Spawning period of this species in the lake was between April and May.     

The population biology of the exploited crab Ucides cordatus (Linnaeus, 1763) in a southeastern Atlantic Coast mangrove area,Brazil

Ucides cordatus (Linnaeus, 1763), found in mangroves along the Brazilian coast, is an artisanal fishery resource harvested as a source of income and for subsistence. A 12?month study of U. cordatus was conducted in a mangrove area of the southeastern Brazilian coast to estimate the growth, longevity, sex ratio and population density of the crabs. A total of 1024 crabs (505 males and 519 females) were sampled. Carapace width (CW) ranged from 49 to 90?mm (mean?±?SD: 71.2?mm?±?6.0) for males and from 52 to 83?mm (69.3?mm?±?4.9) for females. Males dominated the largest CW classes. The asymptotic size (CW_∞) and the asymptotic weight (WW_∞) were estimated as 93.4?mm and 305.5?g, respectively, for males and as 87.1?mm and 221.5?g, respectively, for females. The estimated maximum longevities were 17.6?years for males and 15.7?years for females. The males (k?=?0.17, Φ?=?1.171) and females (k?=?0.19, Φ?=?1.159) showed similar growth rates. The mean density was 0.41?±?0.19?burrows?m^?2. Of this total mean density, 85.8% corresponded to the immediate harvesting potential and 14.2% to the future harvesting potential. Given that U. cordatus is a long-lived species that grows slowly, an appropriate strategy for the management is crucial to ensure the sustainable exploitation of this resource.     

Population parameters and exploitation rate of Sarotherodon galilaeus galilaeus (Cichlidae) in Lakes Doukon and Togbadji,Benin

Growth, mortality, recruitment and relative yield per recruit of Sarotherodon galilaeus galilaeus from Lakes Doukon and Togbadji were studied. Data on total length, total weight and sex were recorded on a monthly basis between January and December 2013 for S. g. galilaeus captured by local fishers. The estimated asymptotic lengths L_∞ were 26.2 and 23.6?cm for Lakes Doukon and Togbadji, respectively, while the growth rate K was 0.73 in Lake Doukon and 0.87 in Lake Togbadji. Estimates of fishing mortality, 0.27 and 0.47 y^?1 for Doukon and Togbadji, respectively, were low relative to natural mortality, 1.51 and 1.74 y^?1, respectively. Sizes at first sexual maturity were 12.8 and 13.2?cm for females and males, respectively, in Lake Doukon, and 11.5 and 12.4?cm for females and males, respectively, in Lake Togbadji. The size at first capture was estimated at 13.3 and 12.7?cm for Lakes Doukon and Togbadji, respectively, which, in the light of the size at maturity estimates, indicates that fish spawn at least once before capture. The current exploitation rates of 0.15 for Lake Doukon and 0.21 for Lake Togbadji suggest that their stocks of S. g. galilaeus are not overexploited in either lake.     

Production of Excirolana armata (Dana, 1853) (Isopoda, Cirolanidae) on an exposed sandy beach in southeastern Brazil

The somatic and gonad productions of the cirolanid isopod Excirolana armata were analyzed by taking monthly samples from December 2003 to November 2005 on Una beach, S?o Paulo state (24°S), southeastern Brazil. Sampling was performed along three fixed transects established from the base of the foredunes to the waterline. Weight-specific growth rate was used to estimate the E. armata somatic production for 2004 and 2005, separately. The gonad production was estimated based on the monthly reproductive potential (mean number of eggs/embryos per female × monthly abundance of ovigerous females with near-release broods) for 2004. The annual somatic production of E. armata population varied from 15.57 to 17.25?g AFDW m^?1?year^?1 and the somatic production/biomass ratio (P _s/B) from 3.55 to 3.14?year^?1 for 2004 and 2005, respectively. The P _s/B ratios were higher for males (4.02 and 3.19?year^?1 for 2004 and 2005) than for females (3.10?year^?1 for both years). The annual gonad production (P _g?=?1.07?g AFDW m^?1?year^?1) contributed about 15 and 6% to the total production (P _s?+?P _g) of females and the population, respectively. The proportion of gonad to somatic production of females (P _g/P _s) increased with individual size (ca 90% in the 7.5?mm size class), and the annual weight-specific gonad production (P _g/B ratio) was estimated to 0.24?year^?1. The high P _s/B ratios estimated for E. armata derive from the fast growth of individuals and show the importance of this population to the energy flow on Una beach ecosystem. However, the low percentage of juveniles verified in this population and in other studies of populations of the genus Excirolana is discussed as an important source of underestimation of P _s/B ratio.     

Vertical distribution by demographic groups of ghost crab Ocypode quadrata (Crustacea: Brachyura)

The ghost crab Ocypode quadrata plays an important role in energy transfer between trophic levels, and has been widely used in evaluations of impacted environments. In order to provide data on the biology of this potential bioindicator species, the population structure and vertical distribution of individuals were studied on two beaches in southeastern Brazil. Each beach was divided into quadrants of 1000 m² with boundaries of upper, middle and lower levels in relation to the waterline. Collected monthly by active searching through one year, the specimens of O. quadrata were sexed, measured for carapace width, and returned to the beach. Of the total of 1904 specimens collected, the largest proportion (46.2%) were males, followed by 31.4% juveniles. The vertical distribution of the ghost crabs differed among age groups: males mostly occupied the middle and upper levels; adult females, ovigerous or not, were more abundant in the lower level; and juveniles were evenly distributed in all levels, with a slight tendency toward the middle. The sex ratio favored males in a few months of the year and in the larger size classes. The abundance of O. quadrata is limited by low temperatures, and its spatial and temporal distribution is controlled by food availability and ease of reproduction. Knowledge of the biology of these crabs is essential in order to use them as a bioindicator species; the vertical distribution patterns may reflect changes in the beach hydrodynamics or other environmental factors.     

Biometric and reproductive aspects of the pen shell Atrina seminuda (Bivalvia: Pinnidae) in northeastern Venezuela

The pen shell Atrina seminuda is a target for a small artisanal Caribbean fishery; however, little is known about its biology. The length frequency distribution, biometric relations and reproduction of this species were studied in northeastern Venezuela. Using transects selected from among 360 stations a population was sampled monthly by SCUBA diving. An analysis of 1748 individuals showed a shell height (SH) between 4?cm and 23.6?cm, with an average of 16.7?±?2.5?cm. For both sexes, statistical differences in mean SH were observed (analysis of variance F (1, 1113)?=?69.538; P?SL), total weight (TW) and adductor muscle weight (MW) as a function of SH. In all cases there were statistical differences between males and females, with males presenting positive allometry and females showing isometry. Mean SH at maturity for males (8.24?cm) was lower than for females (11.88?cm), and for sexes combined was estimated at 8.71?cm. Gametogenic activity was observed throughout the year, with two main peaks of spawning (April and August/September 2008). All this information is crucial for demographic modelling and stock assessment for managing this species.     

Reproductive biology of the silver pomfret, Pampus argenteus (Euphrasen), in Kuwait waters

The reproductive activities of the silver pomfret, Pampus argenteus (Euphrasen), in Kuwait waters were investigated from March 1996 to February 1998. Observations on the seasonal distribution of maturity stages and variations in seasonal fluctuations in the gonadosomatic index (GSI) confirmed recent findings that the spawning period begins in May. The species has a prolonged spawning period in the females extending from May to August, whereas the males mature in April and ripe specimens were encountered in monthly samples until September. The recruitment pattern confirmed the one breeding season. There are two spawning peaks, the first in May and the second in August. Variations in GSI relative to fish length indicated that females and males are most fecund at about 24.5–26.4 cm and 20.5–22.4 cm length classes, respectively. The males mature earlier than females, at a minimum size of 12.5–14.4 cm, while the females mature at 20.5–22.4 cm. The oocyte diameter‐frequency distribution suggests a serial rhythm of spawning. Fecundity ranged from 28 965 to 455 661 and correlated positively with: (a) standard length (P < 0.006); (b) ovary weight (P < 0.001); and (c) body weight (P < 0.001), and negatively with egg size (P < 0.003).     

Biological Aspects of Medorippe lanata (Linnaeus, 1767) (Brachyura: Dorippidae) from the Eastern Ligurian Sea (Western Mediterranean)

The aim of the present study is to investigate the demographic structure and to identify some aspects of the biology of an exploited population of Medorippe lanata (Brachyura: Dorippidae) in the eastern Ligurian Sea, western Mediterranean. 1364 specimens (639 males and 725 females) of M. lanata were collected on a monthly basis from January to December 2001, in a wide area of the eastern Ligurian Sea usually exploited by the Viareggio ‘rapido’ trawl fleet. M. lanata represented an important fraction of the discard, both in weight and in number of individuals. Maximum abundance of this species occurred in late summer-early autumn (up to 3369 ind. km⁻² and 50.6 kg km⁻² in August). The overall females:males sex-ratio was 1.13:1, while the monthly sex-ratio did not differ statistically from 1:1 in all months, except in September and October, when females significantly outnumbered males. The sampled population was composed of two cohorts from November to April. Sizes ranged from 10 to 29 mm carapace length (CL) for females and from 9 to 29 mm CL for males. The von Bertalanffy growth curve, computed for both sexes, gave a higher growth rate in males than in females. Recently moulted males and females were observed throughout the year, except in summer, when the highest number of ovigerous females was present. Females with external eggs were collected from March to November, with peaks in August and September. The monthly evolution of the ovarian maturity stages showed no clear temporal trend. At 21 mm CL, 50% of females were ovigerous or showed macroscopically mature ovaries. According to the dimorphism in chelae size, the presence of adult males (post-puberty stage) was observed all year round, from 18 to 29 mm CL, without evident temporal trends.     

Life history of the sandy beach amphipod Deshayesorchestia deshayesii (Crustacea: Talitridae) from Bizerta beach (North of Tunisia)

Population dynamics and reproductive activity of the amphipod Deshayesorchestia deshayesii were studied monthly from June 2007 to December 2008 in Bizerta beach. During this period, 6577 specimens of D. deshayesii were identified; the sex ratio was female biased, with a mean of the monthly sex ratios equal to 0.21?±?0.12. Due to the absence of embryos or eggs in the female brood pouches and juveniles in the samples, results suggested that the reproductive season extended from April to November, with a sexual resting period during winter from December to March. Brood size varied between 4 and 17 eggs and fecundity appeared to be correlated with female size. Six cohorts were identified on the first sampling date. Additionally, 12 new cohorts were detected during the study period. Life span was estimated at 5–7?months depending on the time of birth. Cohorts that appeared at the beginning of the reproductive period tended to have shorter lives than those born later in the season. These results suggest that D. deshayesii can be considered as a semi-annual species, with iteroparous females.     

Population biology and size at the onset of sexual maturity of the amphidromous prawn Macrobrachium olfersii (Decapoda,Palaemonidae) in an urban river in southeastern Brazil

Abstract

Information on population biology is essential for a better understanding of the ecological stability of a species and the ecosystem in which it lives, especially in areas affected by anthropogenic activities. This study investigated the population biology of Macrobrachium olfersii in an ecosystem under human impact, focusing on sex ratio, reproductive period, and juvenile recruitment. The onset of sexual maturity was also estimated. Samplings were performed monthly in the daytime from June 2006 to May 2007 on the Taquaral River in the city of Ubatuba, São Paulo State, Brazil. The sex ratio was skewed towards females, and both the reproductive period and the juvenile recruitment were continuous. The estimated size at which the species reached sexual maturity corroborated studies on populations from other locations. Results from the current study strongly indicate that the ecosystem studied may have suffered environmental stress, which probably interfered with the migration and establishment of the species: during the study, the species was found in significant abundance, but six years later, it was not captured in samplings.     

Demography of a West African kob (Kobus kob kob) population

The kob (Kobus kob kob) population studied in the Comoé National Park, Ivory Coast, suffered unsustainable losses to poaching before and during the investigation. This in turn did not only lead to low densities but also changed the population composition, resulting in a strong female bias in all age classes except juveniles. The relative rarity of adult males probably had negative effects on the population recruitment. Although mating occurred throughout the year and birth intervals were short, at least in some females, annual birth‐rate was low compared to earlier studies in the same area. Effective conservation measures are urgently needed to ensure the future existence of the studied population.     

Preliminary observations on fecundity of the processid shrimp Nikoides schmitti (Decapoda,Caridea) from Mexican Caribbean

Nikoides schmitti is widely distributed along the Atlantic coast of the Americas, from North Carolina to Bahia, Brazil and Cuba and Guadeloupe; however, the knowledge about their reproductive biology is poorly known. In this study, data such as sex ratio, fecundity, size and volume of the embryos, and brood loss of material collected in July 1997 from Mahahual, Quintana Roo, Mexico is provided. The sample of 728 specimens had a sex ratio of 0.40 males per female. Fecundity (N = 31) of ovigerous females (Stage I) varied from 219 to 817, with an average of 432 ± 177 embryos. The newly extruded embryos of N. schmitti were small (0.41 ± 0.030 mm) and similar in size to those reported for other species of the genus. The mean volume of the embryos changed significantly during development, increasing 60.9% from stages I to III. Embryo loss during incubation was estimated in 32.9%. This study provides baseline information about the reproduction of N. schmitti and contributes to a better knowledge of this species little studied.     

Reproduction,growth and feeding habits of stout beardfish Polymixia nobilis (Polymixiidae) off the Canary Islands (NE Atlantic)

The present study provides fisheries biology knowledge which will allow the implementation of regulatory measures contributing to the sustainability of the fisheries and the conservation of the stout beardfish Polymixia nobilis Lowe, 1838 off the Canary Islands, north eastern Atlantic Ocean. Males ranged between 16.5 and 38.4 cm fork length (FL) and females from 14.2 to 46.5 cm FL. Sex ratio by size classes provided significant differences in classes higher than 36 cm, being clearly unbalanced in favour of females. Individuals in maturing and mature stages were present during all months sampled, although a spawning peak is evident between April and June. Size at first maturity was estimated as 26 cm FL for females and 30 cm FL for males. Age was determined from annuli in whole otoliths. Age range was found to be 0–14 years for fish measuring 14.2 to 46.5 cm FL. It is a slow‐growing and long‐lived species. Significant differences in the growth parameters between sexes were detected. The von Bertalanffy growth parameters estimated for females (n = 213) were L_∞ = 45.92 cm LF, k = 0.16 years^?1 and t₀ = ?2.84 years; and for males (n = 186) L_∞ = 36.44 cm LF, k = 0.26 years^?1 and t₀ = ?2.16 years. Stomach analysis indicated some variations in the feeding habits with growth: individuals of small and medium sizes preyed on crustaceans and fishes, while large specimens preyed mainly on fishes.     

Population demographics of Palaemon peringueyi (Macpherson 1990) (Decapoda: Palaemonidae) in a small intermittently open Eastern Cape estuary

The population demographics of the caridean shrimp Palaemon peringueyi was investigated monthly at four sites over a period of one year in the small, intermittently-open Grants River Estuary situated on the south-east coastline of southern Africa. Mean total abundance and biomass of P. peringueyi ranged between 0 and 23.2 ind m^?2 and 0 and 2.3mg wwt m^?2, respectively. A peak in its abundance coincided with a breaching event that occurred in December 2004, and could be attributed to the mass recruitment of juveniles (carapace length <9mm) into the estuary. Minor peaks in abundance were also associated with marine waters overtopping the sandbar that separates the estuary from the marine environment. The highest biomass values were recorded when the estuary was separated from the sea. Maximum abundance and biomass values of P. peringueyi were generally recorded in the middle reaches of the estuary where extensive beds of submerged vegetation, mainly Potamogeton pectinatus, predominated. Pearson correlation analysis indicated that the total abundance of P. peringueyi was significantly correlated (r = 0.49; p < 0.05) to percentage cover of submerged vegetation. The spatial pattern in abundance and biomass values of the shrimp is thought to reflect the availability of refuge areas against predation. A distinct spatial pattern in the community structure of the shrimp was evident, with juveniles numerically dominating the samples in the lower reaches of the estuary, while mature females predominated in the upper reaches of the system. In the middle reaches, the community comprised both juveniles and adults.     

Initiation of early breeding in a population of Microtus townsendii (Rodentia) with the secondary plant compound 6-MBOA

Summary Feeding the secondary plant compound 6-Methoxybenzoxazolinone (6-MBOA) during winter to a free living population of Microtus townsendii accelerated breeding in females. Both the recruitment of young and sexual maturation of these young were advanced by four weeks in comparison with a control population. Overwintered females supplied with 6-MBOA matured at a lower body weight than control females. But there was no such weightat-maturity difference between the grids for males. During April and May 72% of all juveniles captured came from the experimental population. Winter reproduction and early recruitment of young stimulated by 6-MBOA could have important population consequences for these voles.     

Ecological distribution of the shrimp Pleoticus muelleri (Bate, 1888) (Decapoda: Penaeoidea) in southeastern Brazil

The abundance and ecological distribution of the shrimp Pleoticus muelleri as a function of certain environmental factors were investigated from January 1998 through December 1999 in the region of Ubatuba, São Paulo, Brazil. The collections were made monthly in the bays of Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV). Each bay was divided into six sampling transects, four transects parallel to the shoreline and two near the rocky shores on the opposite side. We employed a commercial shrimp boat equipped with two double-rig nets. A total of 6252 shrimp were collected, including 3321 from MV, 1467 from UBM, and 1464 from UBA. Most of the shrimp were caught in the deeper, higher-salinity areas. The high abundance of P. muelleri observed in the southern part of the region studied was related to a sediments with a higher percentage of silt and clay. The numbers of P. muelleri were positively correlated with periods of cooler temperatures. Thus, temperature and the type of sediment were determinant factors in the distribution of P. muelleri in this region.     

Bionomics and morphological and molecular characterization of Elasmus schmitti and Baryscapus elasmi (Hymenoptera: Chalcidoidea, Eulophidae), parasitoids associated with a paper wasp, Polistes dominulus (Vespoidea, Vespidae)

Elasmus schmitti and Baryscapus elasmi have been recorded in southern Ukraine as gregarious parasitoids in the nests of the paper wasps Polistes dominulus and Polistes nimphus. Polistes dominulus nests infested with E. schmitti were less productive than uninfested nests in only one year (2004) of the three years of the present study, when an increase in the host population size occurred. Females of E. schmitti are synovigenic, and they lay their eggs on the skins of P. dominulus last instar larvae, without paralyzing the host. Rather, the parasitoid larvae feed on young host pupae. The pupae of E. schmitti are isolated from the host remnants by a thin fecal partition as in Elasmus polistis and Elasmus japonicus, other paper wasp parasitoids. Baryscapus elasmi is a pupal endoparasitoid of E. schmitti. The females of B. elasmi emerge without mature eggs in their ovaries and mate with males. They penetrate the paper wasp’s cells with their ovipositor and feed on the extracted hemolymph exudate. Pupation of B. elasmi occurs inside or outside the pupa of the host, E. schmitti. If inside, then the cranial end of the pupa and the adult emergence hole of B. elasmi are situated in the caudal ends of the pupae of their hosts. Comparative notes and illustrations on the morphology of adults are provided, and DNA sequences of three genes (nuclear 28S D2 rDNA, mitochondrial cytochrome oxidase subunit I, and mitochondrial cytochrome b) were obtained for both parasitoid species. The similarity of the 28S D2 sequences of E. schmitti and E. polistis relative to other available Elasmus sequences suggests a single origin of parasitism on paper wasps in this genus.