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To investigate the expulsion of radiotransmitters in snakes and modify the surgical technique for coelomic implantation to prevent its occurrence. To enable monitoring of snakes for an ecological study, radiotransmitters were implanted in 23 south-west carpet pythons ( Morelia spilota imbricata) using the standard surgical technique. In a further 23 pythons we used a refinement of the technique, which anchored the tracking device, using non-dissolvable sutures, to the snake's rib-cage. We also investigated the potential mechanisms for expelling the radiotransmitters in one snake that underwent an exploratory coeliotomy. Of the initial group of snakes, 12 (52%) expelled the radiotransmitter between 4 days and 3 years post implantation. In the later group, which underwent the refined technique of implantation, none of the radiotransmitters was expelled and no adverse responses were observed. An appropriately sized radiotransmitter anchored to the rib-cage of the snake will prevent expulsion of the device and appears to be well tolerated. Non-attachment of the tracking device enables it to migrate along the length of the body, particularly during feeding and reproduction. Caudal positioning of the transmitter's antenna provides a possible pathogenesis for expulsion into the cloaca. [ABSTRACT FROM AUTHOR]

Abstract: Insulin-like growth factor-1 (IGF-1) is a peptide hormone critically involved in the regulation of key life-history traits such as growth and reproduction. Its structure and function are well-characterized among diverse mammal, fish, and bird species; however, little is known regarding the activities of IGF-1 in non-avian reptiles, particularly snakes and lizards. Nevertheless, several unique characteristics of reptiles, such as high metabolic flexibility and remarkable diversity in life-history strategy, suggest that they are of great interest in the study of endocrinological mechanisms underlying the regulation and evolution of life-history traits. Here we test for a relationship between IGF-1 and individual feeding rate, growth rate and reproductive stage in lab-reared female offspring of wild-caught oviparous house snakes, Lamprophis fuliginosus. We confirm a positive correlation between IGF-1 and both feeding and growth rates in sexually immature snakes, similar to that reported in other taxa. We also show a family effect on IGF-1, suggesting that IGF-1 levels may be heritable in these snakes, and serve as an important target of selection to produce divergent life-history strategies. Furthermore, we provide evidence that suggests that IGF-1 may peak rapidly after first mating, and subsequently decline prior to egg-laying, a phenomenon not previously reported in other taxa. These findings suggest that further comparative study of IGF-1 in snakes may reveal both the extent to which IGF-1 function is conserved across major taxonomic groups, as well as novel and intriguing roles for IGF-1 in the regulation of reproductive activities. [ABSTRACT FROM AUTHOR]

Anthropogenic habitat modification often creates barriers to animal movement, transforming formerly contiguous habitat into a patchwork of habitat islands with low connectivity. Roadways are a feature of most landscapes that can act as barriers or filters to migration among local populations. Even small and recently constructed roads can have a significant impact on population genetic structure of some species, but not others. We developed a research approach that combines fine-scale molecular genetics with behavioral and ecological data to understand the impacts of roads on population structure and connectivity. We used microsatellite markers to characterize genetic variation within and among populations of timber rattlesnakes (Crotalus horridus ) occupying communal hibernacula (dens) in regions bisected by roadways. We examined the impact of roads on seasonal migration, genetic diversity, and gene flow among populations. Snakes in hibernacula isolated by roads had significantly lower genetic diversity and higher genetic differentiation than snakes in hibernacula in contiguous habitat. Genetic-assignment analyses revealed that interruption to seasonal migration was the mechanism underlying these patterns. Our results underscore the sizeable impact of roads on this species, despite their relatively recent construction at our study sites (7 to 10 generations of rattlesnakes), the utility of population genetics for studies of road ecology, and the need for mitigating effects of roads. [ABSTRACT FROM AUTHOR]

Abstract: We describe the reproductive cycle of Northern Pacific rattlesnakes (Crotalus oreganus) by quantifying steroid hormone concentrations and observing reproductive behaviors in free-ranging individuals. Additionally, we examined reproductive tissues from museum specimens. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (March–October). We measured testosterone (T), 5α-dihydrotestosterone (DHT), and corticosterone (B) concentrations in both sexes and 17β-estradiol (E2) and progesterone (P) in females only. We observed reproductive behaviors (e.g., consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum collections to relate steroid hormone concentrations to the timing of reproductive events. Our study revealed that C. oreganus in central California exhibits a bimodal pattern of breeding, with most mating behavior occurring in the spring and some incidences of mating behavior observed in late summer/fall. Each breeding period corresponded with elevated androgen (T or DHT) levels in males. Testes were regressed in the spring when the majority of reproductive behavior was observed in this population, and they reached peak volume in August and September during spermatogenesis. Although we did not detect seasonal variation in female hormone concentrations, some females had high E2 in the spring and fall, coincident with mating and with increased follicle size (indicating vitellogenesis) in museum specimens. Females with high E2 concentrations also had high T and DHT concentrations. Corticosterone concentrations in males and females were not related either to time of year or to concentrations of any other hormones quantified. Progesterone concentrations in females also did not vary seasonally, but this likely reflected sampling bias as females tended to be underground, and thus unobtainable, in summer months when P would be expected to be elevated during gestation. In females, P was positively correlated with T and DHT, and E2 was positively correlated with T. [Copyright &y& Elsevier]

Mediterranean vipers are ecologically very similar. When in contact, they constitute an exceptional model to study the effects of competitive interactions and niche segregation mechanisms. In High Ebro, distinct methodologies (random visual encounter, road sampling and radio-tracking surveys, captive maintenance, standardized transects and ad hoc field observations) were used to compare ecological traits (diet, micro-habitat, activity, reproductive and demographic) of V. aspis, V. latastei and hybrids among both species and determine competitive advantages of each form. Diet preferences were similar but few differences were found in feeding frequency and annual variation in diet consumption. Males of the three forms compete for areas with similar characteristics but differences were found mainly during summer. Significant differences in average movement rates and home range size were found among males. Fecundity and new-borns fitness were lower in V. aspis than in V. latastei, whereas hybrids had intermediate values. Male and female adult hybrids were more abundant than parental forms, whereas female and juvenile V. latastei and juvenile hybrids had high road-mortality. The three forms seem to be competing intensely for resources but the segregation on the spatial and temporal axes of their niches could be reducing interspecific competition and allowing coexistence. The use of different resources probably confers reproductive and demographic advantages for V. latastei and hybrids, respectively. Moreover, reproductive fitness of hybrids suggests the occurrence of endogenous selection. Comparative thermal and genetic studies are needed to clarify the limiting factors of vipers and to establish a model of the hybrid zone. [ABSTRACT FROM AUTHOR]

Common tree snakes, Dendrelaphis punctulatus, are medium to large colubrid snakes that are relatively common in the eastern and northern parts of tropical Australia. The only previous study on this species involved museum specimens from across the taxon’s range. During a seven-year period we collected data on 131 field-caught specimens from a melanotic population in the Townsville district of north Queensland. Dendrelaphis punctulatuswas found to be primarily diurnal, with a peak in activity centred around the reproductive period during the transition from dry to wet seasons. Females were larger than males with respect to all measured parameters, including mass and head size. Reproduction in females was strongly seasonal and clutch size was related to maternal body size. Prey items consisted of frogs, lizards and locusts. [ABSTRACT FROM AUTHOR]

Although rattlesnakes give birth to living young, the belief that they lay eggs persisted in the midwestern United States until the end of the nineteenth century. This is illustrated by the writings of two prominent chroniclers of natural history in early Winona, a Mississippi River town in southeastern Minnesota. Lafayette Bunnell's accounts of a massacre of timber rattlesnakes ( Crotalus horridus) included statements that a large number of their eggs were also destroyed. The college professor John Holzinger, however, dissected a female rattlesnake to reveal late-term embryos and suggested that the eggs found in the vicinity of rattlesnakes were laid by other species of snakes that share their dens. [ABSTRACT FROM AUTHOR]

The article describes the winter mating activity of the Puff Adders, Bitis arietans found in Gauteng, South Africa. The free ranging snakes were fitted with transmitters to monitor their sexual activity. Up to four males were observed to be attending a single female snake. Based on this observation, it is concluded that during mating, male Puff Adders could come into contact with each other which could result to male-to-male combat.

Abstract: The terciopelo Bothrops asper is the only lancehead species widely distributed in the humid lowlands of Middle America and northwestern South America. Its large body size, relative abundance and cryptic habits contribute to the high incidence of snakebites induced by this species throughout its distribution. The terciopelo plays an important role in ecosystems, both as prey and as a generalist predator. Diet comprises a great variety of prey items, including some species that are considered nuisances. B. asper, as other lancehead species, exhibits a notable ontogenetic shift in diet, consuming ectotherms (mainly frogs and lizards) when young, and increasingly incorporating birds, rodents, and other small mammals with maturity. Adult terciopelos also consume large anurans, especially when endothermic prey availability is low. Using radiotelemetry we determined home range and movement patterns from 28 individual B. asper at La Selva Biological Station, Costa Rica. Overall home range estimates are relatively small compared with other pitvipers, averaging between 3.71ha and 5.95ha; home range size did not differ between males and females. Movement patterns are largely aseasonal and consist of short (<10m) movements between daytime shelter and nocturnal ambush sites within a given area, interspersed with longer distance (>50m) movements to new foraging areas. Habitat use is related to prey availability and therefore to foraging strategy. Our data support a strong preference for areas near swamps by both sexes. Reproduction in B. asper is highly seasonal, and – apparently – biannual. Reproductive cycles in Costa Rica are tightly related to rainfall patterns. Therefore, the timing of breeding differs between populations in the Caribbean and Pacific lowlands. Bothrops asper is adapted to areas with low levels of disturbance along the agricultural frontier, and consequently it is not rare to find it in or near human dwellings. However, despite popular belief, no evidence supports a purported increase in population density of this species in Costa Rica. Despite human persecution and substantial modification of habitat, B. asper is a species with a conservation status of least concern, and probably will likely persist well into the future. Thus, it is important to learn how to coexist with this species, and to improve mechanisms for the prevention and treatment of accidental snakebite and its consequences. [Copyright &y& Elsevier]

Identifying links between phenotypic attributes and fitness is a primary goal of reproductive ecology. Differences in within-year patterns of body condition between sexes of gartersnakes in relation to reproduction and growth are not fully understood. We conducted an 11-year field study of body condition and growth rate of the giant gartersnake Thamnophis gigas across 13 study areas in the Central Valley of California, USA. We developed a priori mixed effects models of body condition index (BCI), which included covariates of time, sex and snout–vent length and reported the best-approximating models using an information theoretic approach. Also, we developed models of growth rate index (GRI) using covariates of sex and periods based on reproductive behavior. The largest difference in BCI between sexes, as predicted by a non-linear (cubic) time model, occurred during the mating period when female body condition (0.014±0.001 se) was substantially greater than males (−0.027±0.002 se). Males likely allocated energy to search for mates, while females likely stored energy for embryonic development. We also provided evidence that males use more body energy reserves than females during hibernation, perhaps because of different body temperatures between sexes. We found GRI of male snakes was substantially lower during the mating period than during a non-mating period, which indicated that a trade-off existed between searching for mates and growth. These findings contribute to our understanding of snake ecology in a Mediterranean climate. [ABSTRACT FROM AUTHOR]

The article focuses on the geographic distribution extension, geogarphic variation, and collection of reptilia species Leptotyphlops salgueiroi in Brazil. It notes that there are 14 species of the genus Leptotyphlops throughout the country. It evaluates the assumptions as to the univariate homoscedasticity and normality of the L. salgueiroi species using Kolmogorov-Smirnov and Levene tests. It points out that this species has a more continental distribution than the previous data. Moreover, its analysis of variance was employed for the verification of sexual dimorphism's existence.

Abstract: The insufficient supply of wild sponge biomass, i.e., “the supply problem,” critically limits the development of sponge-derived bioactive natural products and other applications. Intensive aquaculture of sponges through artificial seed rearing may provide an alternative sustainable supply of sponge biomass. To develop the technology of sponge aquaculture, protocols for artificial seed production need to be established. To understand larval release and settlement under artificial controlled environments, a model marine sponge Hymeniacidon perlevis was investigated under controlled laboratory conditions. The larval release of H. perlevis is an asynchronous event in the laboratory-controlled environment. Sponge explants attached on substrata release 5 times more larvae than unattached sponge explants. Over the course of 12 days of release, the mean release rate was 7.2 larvae g−1 wet sponge day−1 for attached sponges. Over the course of 7 days of release for unattached sponges, the mean release rate was 2.6 larvae g−1 wet sponge day−1. Light (6000 lx) stimulated the sponges to release more larvae than did dark incubation. The highest number of sponge larvae (195.8 larvae g−1 wet sponge) was released at 18 °C, while only 48 and 51.7 larvae g−1 wet sponge were released at 14 °C and 25 °C, respectively. Larval settlement was favored in dark condition. The highest percentage of larvae settled at 22 °C, among all temperatures tested. [Copyright &y& Elsevier]

We studied the reproductive and trophic ecology of a group of aquatic and semi-aquatic snakes that face severe hunting pressure in Cambodia. Over a two-year period we sampled hunters' catches, measuring and dissecting a total of 8982 specimens of seven snake species, five of which belong to the family Homalopsidae. The seven species--Enhydris enhydris, Enhydris Iongicauda, Homalopsis buccata, Enhydris bocourti, Erpeton tentaculatus, Xenochrophis piscator, and Cylindrophis ruffus--all inhabit Tonle Sap Lake, the largest lake in South-East Asia. All species are sexually dimorphic in either body size or tail length. The larger species, E. bocourti and H. buccata, have a larger size at maturity, and the nonhomalopsids, X. piscator and C. ruffus, have the highest and lowest fecundities, respectively. Clutch size increases significantly with female body size in all species, and with body condition in E. enhydris. Our data also suggest that relative investment in reproduction increases with size in E. enhydriso which has the largest sample size. All species except one are synchronized in their timing of reproduction with the seasonally receding flood waters of the lake. There was variation in both the frequency of feeding and the prey size and type among species, with the homalopsids more similar to one another than to the other non-homalopsid species. The prey to predator mass ratio ranged from 0.04 to 0.1 in the homalopsids, compared to 0.15 to 0.17 in the non-homalopsids. There was also variation in the feeding frequency between the sexes that differed between species and six species continued to feed while gravid. These detailed life history analyses can help provide a basis for assessing conservation options for these heavily exploited species. [ABSTRACT FROM AUTHOR]

Abstract: We collected 20 checkered keelback snakes (Xenochrophis piscator) to study embryonic growth and mobilization of energy and material during incubation. Females laid eggs between late May and late June. The eggs were incubated at 27 °C (±0.3). One egg from each clutch was dissected at five-day intervals starting at oviposition. The mean incubation length at 27 °C was 48.9 days. We identified three phases of embryonic growth or yolk depletion in X. piscator. Phase 1, between oviposition and Day 20, was one of minimal transfer of energy and material from yolk to embryo. Phase 2, between Day 20 and Day 39–40, was characterized by increasingly rapid embryonic growth or yolk depletion. Phase 3, between Day 39–40 and hatching, was characterized by reduced embryonic growth or yolk depletion. Approximately 71% of dry mass, 53% of non-polar lipids and 66% of energy were transferred from the egg contents to the hatchling during incubation. Our data confirm that oviposition is not timed to coincide with the onset of rapid embryonic growth in oviparous squamate reptiles. The greater conversion efficiencies of energy and material from egg to hatchling in snakes can be attributed to their lower energetic costs of embryonic development and greater residual yolk sizes. [Copyright &y& Elsevier]

Slaty grey snakes (Stegonotus cucullatus) are medium to large members of the Colubridae that are common throughout the eastern and northern tropics of Australia. Although intensive field studies have been conducted on populations in the Northern Territory for over 10 years, no ecological data have been presented on free-ranging specimens of populations inhabiting tropical north Queensland. During a 10-year period we collected opportunistic data on 120 free-ranging specimens from the seasonally Wet Tropics in north Queensland. These snakes provided data on body sizes, activity times, food habits and reproduction. Male S. cucullatuswere larger than females and had larger heads. More snakes were found during the warmer, humid parts of the year (wet season). S. cucullatusate a wide range of vertebrate prey, including reptile eggs that were obtained seasonally. Females produced one clutch per year, and no relationship was found between maternal snout–vent length and clutch size. [ABSTRACT FROM AUTHOR]

Two species of large black whip snakes (Demansia vestigiataand D. papuensis) are morphologically and ecologically similar and have broadly overlapping distributions. A long history of taxonomic difficulties has meant that most previous taxonomic and ecological studies comprise composite samples of both taxa. Here, we provide ecological data (body sizes, food habits, reproduction and inferred growth rates) collected from captured and road-killed specimens from a tropical population of D. vestigiataat Townsville, north-eastern Queensland, Australia. Males attain larger body sizes and have longer tails than females. All food items were ectotherms (lizards and frogs). Female reproductive cycles were strongly seasonal. Clutch size is significantly positively related to maternal body size. Egg dimensions, clutch mass and neonatal size are reported. Inferred growth rates indicate that sexual maturation is attained at ~21 months for females. [ABSTRACT FROM AUTHOR]

Information on the phenotypic correlates of male reproductive success can provide important insights into the operation of sexual selection, and the nature of evolutionary forces on phenotypic traits such as male body size. We combined results from a long-term mark–recapture field study with genetic analyses for identifying paternity of offspring to quantify male reproductive success in a colubrid snake species from tropical Australia. Because previous work has shown that male slatey-grey snakes, Stegonotus cucullatus, attain larger body sizes than do conspecific females, we predicted that larger males would have higher reproductive success. Our paternity assignments of 219 offspring (24 clutches) supported this prediction: larger males fathered more offspring, not because they obtained more matings, but because they fathered a higher proportion of offspring within the clutches to which they did contribute. Multiple paternity was common (mean of 2.3 fathers per clutch, range 1–5). Our results demonstrate the utility of molecular approaches to clarify mating systems in field populations of snakes, and suggest that the evolution of extreme male-biased sexual size dimorphism in this species is attributable to enhanced reproductive success afforded by larger body size in males. [Copyright &y& Elsevier]

Abstract: To better understand the proximate causation of the two major types of mating seasons described for North American pitvipers, we conducted a field study of the cottonmouth (Agkistrodon piscivorus) in Georgia from September 2003 to May 2005 that included an extensive observational regime and collection of tissues for behavioral, anatomical, histological, and hormone analysis. Enzyme immunoassays (EIA) of plasma samples and standard histological procedures were conducted on reproductive tissues. Evidence from the annual testosterone (T) and sexual segment of the kidney (SSK) cycle and their relationship to the spermatogenic cycle provide correlative evidence of a unimodal mating pattern in this species of pitviper, as these variables consistently predict the mating season in all snake species previously examined under natural conditions. In most reptiles studied to date, high plasma levels of T and corticosterone (CORT) coincide during the mating period, making the cottonmouth an exception to this trend; we suggest two possible explanations for increased CORT during spring (regulation of a spring basking period), and decreased CORT during summer (avoiding reproductive behavioral inhibition), in this species. [Copyright &y& Elsevier]

During pregnancy, the metabolic rate of females may increase above basal levels to support metabolically active tissues and developing embryos. In mammals, this energetic cost of supporting the pregnancy (MCP) is an important component of reproductive effort, but less is known about the magnitude of this cost in ectothermic vertebrates. We estimated the metabolic cost of supporting pregnancy in a tropical viviparous snake, the Northern Death Adder, Acanthophis praelongus. We measured the metabolic rates of non-gravid and gravid females throughout gestation and following parturition. We also measured the oxygen consumption of a sample of neonates from each clutch within 24 h of birth. The metabolic rate of gravid females rose slowly during pregnancy, but was significantly elevated during the last three weeks of gestation. Considering the late term metabolism of gravid females as 100%, then the baseline metabolism of female Death Adders represented 36.6%, embryo metabolism accounted for 37.0%, and the cost of supporting the pregnancy was 26.4% of the total metabolic rate. Neonate metabolism during the first 24 h of birth was 2.9 times higher than the estimate for embryo metabolism. Thus, our results do not support the assumption that the metabolism of embryos (prior to birth) and neonates is similar in this species. Although gravid female Death Adders maintain high and constant body temperatures during late gestation, the energetic cost of supporting the pregnancy is only a minor component of the total reproductive effort for females of this species. [ABSTRACT FROM AUTHOR]

According to the maternal manipulation hypothesis, females manipulate the phenotypes of their offspring by selecting favourable incubation conditions. In oviparous black ratsnakes (Elaphe obsoleta Say in James, 1823), females manipulate offspring phenotype through nest-site selection. This study aimed to determine whether the thermal mean and variance of the incubation regime affect fitness-related traits in hatchlings. We incubated 136 eggs in a split-clutch design at two thermal means (26 and 29 °C) and variances (constant and ±3 °C). Hatchlings incubated at higher temperatures hatched earlier, were longer, faster, and less defensive. Hatchlings incubated at constant temperatures hatched earlier and were longer. For athletic performance, there was a significant interaction between temperature mean and variance: hatchlings incubated at 29 °C swam faster, had a lower muscular strength, and righted themselves equally fast when incubated at constant temperatures, whereas hatchlings incubated at 26 °C were stronger, swam faster, and righted themselves more slowly. Overall, constant incubation temperatures produced hatchlings with phenotypes favouring higher survival than fluctuating temperatures, but the effect of thermal variance was not as pronounced as the effect of thermal mean. Therefore, we found some support for the hypothesis that black ratsnakes prefer communal over single-female nests because communal nests have higher, more constant temperatures. L’hypothèse de la manipulation maternelle veut que les femelles manipulent les phénotypes de leurs rejetons en choisissant des conditions favorables d’incubation. Chez la couleuvre obscure (Elaphe obsoleta Say in James, 1823) qui est ovipare, les femelles manipulent le phénotype de leurs rejetons par leur choix du site de nidification. Notre étude cherche à déterminer si la moyenne et la variance de la température du régime d’incubation affectent les traits reliés à l’aptitude chez les nouveau-nés. Nous avons incubé 136 œufs, d’après un plan expérimental de couvées divisées, à deux moyennes (26 et 29 ºC) et deux variances (température constante et ±3 ºC) de température. Les nouveau-nés incubés aux températures plus élevées éclosent plus tôt, ils sont plus longs, plus rapides et moins défensifs. Les nouveau-nés incubés à des températures constantes éclosent plus tôt et sont plus longs. Il y a une interaction significative entre la moyenne et la variance de température en ce qui a trait à la performance athlétique : les nouveau-nés incubés à 29 ºC nagent plus vite, possèdent une force musculaire plus faible et se redressent à la même vitesse lorsqu’ils sont incubés à température constante; en contraste, les nouveau-nés incubés à 26 ºC sont plus forts, nagent plus rapidement et se redressent moins vite. Globalement, l’incubation à température constante produit des nouveau-nés qui possèdent des phénotypes qui favorisent une meilleure survie que l’incubation à température fluctuante; cependant, les effets de la variance de température ne sont pas aussi prononcés que ceux de la moyenne. Nous trouvons donc un certain appui pour l’hypothèse qui veut que les couleuvres obscures préfèrent les nids communautaires aux nids de femelles solitaires, parce que les nids communautaires ont des températures plus élevées et plus constantes. [ABSTRACT FROM AUTHOR]

Two spermatogenetic cycles, vernal and aestival, have been described in temperate colubrid snakes. In both cycles, mating occurs in the spring, although vernal species produce spermatozoa in spring, just before mating, while aestival species use spermatozoa produced the previous summer. In this study, we describe the reproductive cycles of male and female Malpolon monspessulanus (Colubridae), and compare them to previously published cycles of five other snake species, four vernal and one aestival, inhabiting the same area. We also examine the consequences of both spermatogenesis cycles over the entire reproductive processes of male and female snakes in the south-eastern Iberian Peninsula. Vernal species mate later than do aestival species, as males must produce spermatozoa just prior to mating. However, vernal species are able to condense spermatogenesis and vitellogenesis processes, hence undertaking oviposition at the same time as aestival species. Here we discuss advantages of accomplishing the entire reproductive cycle in one (vernal species) or two (aestival species) calendar years. We also found that mature male M. monspessulanus exhibit decreased testes volume relative to body size. Large testes are expected in scenarios of sperm competition. The mating system of M. monspessulanus (territoriality, mate guarding, male-male combat) does not suggest sperm competition, hence it may be more advantageous for males of this species to invest in body size than in testes size. [ABSTRACT FROM AUTHOR]

The reproductive output of sponges possessing small elusive larvae remains little investigated, even though they are relevant community members in many cases. This makes difficult to understand their life cycles and population dynamics. In this study we monitored the dynamics of embryogenesis and larval output in a north-western Mediterranean population of the sublittoral demosponge Corticium candelabrum. The sponge was moderately abundant, mostly concentrated at overhangs and shaded walls. The population was dominated by relatively small individuals, averaging 1.26 cm3 in size. About 89% of individuals in the population produced gametes. Body size did not preclude reproduction, as gametes and embryos occurred in sponges ranging from 0.24 to 13.5 cm3 in size. On average, individuals produced 21.3 ± 12 embryos per mm3 of sponge tissue, but inter-annual variability in the reproductive effort was noticed. Larval release was asynchronous at both the individual and the population level, with sponges releasing larvae from early July to August. A yearly production was estimated of about half a million larvae per m2 of rocky bottom at those sites where this species occurs. Living larvae measured 340 ± 25 μm in length, were bulb-shaped, entirely ciliated, and swam with a clockwise rotation. They were hollow, with an internal cavity limited by a monolayered epithelium of columnar cells. All larval cells had a distal cilium arising from a principal centriole connected to a basal foot. There was an orthogonal accessory centriole giving rise to a short striated rootlet (21-nm periodicity band) that ran between the nucleus and the Golgi apparatus. This is the first reported case in Porifera of a ciliary rootlet derived from an accessory centriole, an uncommon arrangement also found in choanoflagellates. Despite sharing many features, cells of the anterior, medial, and posterior larval region were easily distinguishable from each other because of differences in their internal organization and yolk content. At the distal and proximal poles of all cells, the plasmalemma thickened to produce special junctions and seal the larval epithelium. Distal junctions were septate. The larval cavity was filled with vertically transmitted symbiotic bacteria and collagen fibrils. Collagen condensed below the larval epithelium at different degrees, but was absent in some areas, raising doubts about the occurrence of a true basement membrane. Larvae showed neither recognizable photoreceptory organelles nor evident behavioral responses to experimental light cues. Because the high larval production does not mirror adult abundance in the community, we suspect high levels of larval losses during dispersal and elevated impact of post-settlement mortality as the probable result of unselective settlement at unsuitable sites. [ABSTRACT FROM AUTHOR]

Reproductive power is a contentious concept among ecologists, and the model has been criticized on theoretical and empirical grounds. Despite these criticisms, the model, has successfully predicted the modal (optimal) size in three large taxonomic groups and the shape of the body size distribution in two of these groups. We tested the reproductive power model on snakes, a group that differs markedly in physiology, foraging ecology, and body shape from the endothermic groups upon which the model was derived. Using detailed field data from the published literature, snake-specific constants associated with reproductive power `were determined using allometric relationships of energy invested annually in egg production and population productivity. The resultant model accurately predicted the mode and left side of the size distribution for snakes but failed to predict the right side of that distribution. If the model correctly describes what is possible in snakes, observed size diversity is limited, especially in the largest size classes. [ABSTRACT FROM AUTHOR]

Abstract: Bothrops insularis is a threatened snake endemic to Queimada Grande Island, southern coast of São Paulo, Brazil, and the occurrence of sexual abnormalities in males, females and intersexes (females with functional ovaries and rudimentary hemipenis) has been reported in this population. The aim of this study was to identify ontogenetic shifts in protease expression of offspring of captive-bred B. insularis. Three neonates from a single litter were maintained at the facilities of Laboratory of Herpetology, Institute Butantan, for 41 months. The snakes were individually milked and venoms were analyzed both by SDS–PAGE, under reducing conditions, and for biochemical activities. The venoms from the mother and from a pool of adult specimens were used as references. In regard to the electrophoretic patterns, common bands were identified mainly between 14 and 50 kDa among snakes. The occurrence of proteolytic activity was noticed predominantly between 27 and 45 kDa in zymograms. Inhibitory assays with 1,10-phenantroline (10 mM) and PMSF (5 mM) showed that venoms possessed both metalloproteases and serine proteases. Venoms of young specimens showed a higher coagulant activity than those of adults, especially upon factors X and II. All venoms presented fibrino(geno)lytic activity, degrading Aα and Bβ chains of fibrinogen, and lysing fibrin plate. These findings can reflect important individual, ontogenetic and sexual differences on venom composition and are likely correlated with diet habits of this species. [Copyright &y& Elsevier]

1. Most life-history models assume a trade-off between reproductive investment and parental survival. Several studies have documented reproductive costs in terms of reduced locomotor performance in terrestrial habitats. However, few studies have determined the reproductive costs of pregnancy in aquatic environments, or compared pregnancy-induced locomotor costs among habitats. This knowledge gap is important because many organisms rely on multiple habitat types during pregnancy. 2. We compared sexual differences in maximum locomotor velocity and the relative impacts of pregnancy on locomotor performance in aquatic and terrestrial environments for a semi-aquatic snake ( Seminatrix pygaea). In addition, because most life-history models predict a direct trade-off between reproductive investment and reproductive costs, we quantified the relationship between reproductive investment and postpartum increase in velocity for both habitat types. 3. Both males and non-pregnant females always swam faster than they crawled, but males were significantly faster for their size than were non-pregnant females. These results mirror sexual differences known to exist in other snakes, but differ in that the degree of sexual divergence in velocity does not vary with habitat for S. pygaea. 4. Pregnancy significantly reduced both crawling and swimming velocity. Moreover, pregnancy impaired crawling velocity significantly more than swimming velocity. The mean ( ± 1 SE) percentage increases in crawling and swimming velocity after parturition were 72·8 ± 21·6 and 59·4 ± 12·8%, respectively. There was a direct trade-off between reproductive investment and aquatic locomotor impairment: snakes that invested more in offspring experienced larger decreases in swimming velocity. However, evidence for such a trade-off in the terrestrial habitat was weaker. 5. Our results demonstrate that the cost of reproduction for semi-aquatic organisms may differ between aquatic and terrestrial habitats in complex ways. Swimming may be more effective than crawling for escaping predators during pregnancy, because swimming results in faster velocities and is less impaired by pregnancy. However, the assumption of a direct trade-off between reproductive investment and locomotor impairment may be stronger for swimming performance compared with crawling performance. [ABSTRACT FROM AUTHOR]

The vomeronasal organ (VNO) is important for activating accessory olfactory pathways that are involved in sexually dimorphic mating behavior. The VNO of male garter snakes is critically important for detection of, and response to, female sex pheromones. In the present study, under voltage-clamp conditions, male snake VNO neurons were stimulated with female sexual attractiveness pheromone. Thirty-nine of 139 neurons exhibited inward current responses (reversal potential: −10.6 ± 2.8 mV). The amplitude of the inward current was dose dependent, and the relationship could be fitted by the Hill equation. Under current-clamp conditions, application of pheromone produced membrane depolarizing responses and increases in firing frequency. These results suggest that the female pheromone directly affects male snake VNO neurons and results in opening of ion channels, thereby converting the pheromone signal to an electrical signal. The response to female pheromone is sexually dimorphic, that is, the pheromone does not evoke responses in VNO neurons of female snakes. An associated finding of the present study is that the female sex pheromone, which is insoluble in aqueous solutions, became soluble in the presence of Harderian gland homogenate. [ABSTRACT FROM AUTHOR]

Bothrops pubescens is a member of the neuwiedi complex that occurs in southern Brazil and Uruguay. We studied the ecology of B. pubescens from a field site (at Santa Maria, Rio Grande do Sul, Brasil) and based on preserved specimens from the state of Rio Grande do Sul, Brasil. In Santa Maria, individuals were collected during visual encounter surveys (VES), in pitfall traps with drift fences and during incidental encounters. Most snakes found in the field were on the ground, mainly on leaf litter, in mosaics of light and shadow or in completely shaded areas. In disturbed areas, snakes were usually associated with country houses and agricultural fields. Snakes were found much more frequently in forests and forest edges than in open habitats. The diet of B. pubescens comprised small mammals (56.2% of individual prey found), anurans (21.2%), lizards (7.5%), snakes (7.5%), birds (5.0%), and centipedes (2.5%). Prey predator mass ratios ranged from 0.002–0.627, and larger snakes tended to consume larger prey. Bothrops pubescens seems to be able to survive in disturbed areas, mainly those close to forests, and this ability may be facilitated by its generalized feeding habits. [ABSTRACT FROM AUTHOR]

Sexual selection and mating systems profoundly influence the behavior and psychology of animals. Using their own studies of green anacondas (Eunectes murinus) and reviewing other recent studies, the authors conclude that incomplete data derived from a few wall-studied snake species have led to general acceptance of polygyny as the dominant mating system in snakes. New data on behavior, paternity, and life history in a diverse taxonomic array of snakes support the view that polyandry is not only common in snakes but may have been the ancestral mating system. This interpretation helps to explain many seemingly paradoxical behavioral differences between lizards and snakes, such as the lack of territorial systems in most snakes and their frequent female-biased sexual size dimorphism. [ABSTRACT FROM AUTHOR]

The storage and utilization of energy plays a critical role in reproductive output for females of many species, including snakes. However, links between energy and reproductive effort in males are less clear. Studies at a communal den of red-sided garter snakes (Thamnophis sirtalis parietalis (Say, 1823)) in Manitoba suggest that energy is critical to reproduction for males as well as females. Males vary substantially in body condition (mass relative to body length) at the time they emerge from winter inactivity. The energy to be expended in courtship is stored in the muscles rather than the "conventional" sites for energy storage in snakes (abdominal fat bodies or liver). A male's reproductive effort (the duration of his residency at courting aggregations near the den) was linked to his energy stores and to the rate of depletion of those stores. Male snakes that emerged from hibernation in better condition, and that lost mass slowly thereafter, remained in courting aggregations near the den for longer periods than did males that emerged in poor condition (i.e., with less energy resources) and (or) lost mass more rapidly. In outdoor arenas, males that engaged in courtship lost mass more rapidly than did males with no courtship opportunities. These data suggest that courtship is energetically expensive for male garter snakes and that the amount of effort that a male invests in reproduction is determined by his energy stores. [ABSTRACT FROM AUTHOR]

1. Understanding the trade-off females make between offspring size and number requires knowing how neonatal size, and traits associated with size, affect survival.2. We studied neonatal survival in the northern watersnakeNerodia sipedonin outdoor enclosures with artificial hibernation sites.3. From a total of 950 neonates from 77 litters collected over 3 years, we found a survival rate of 65% between birth and hibernation and 47% during hibernation. Estimated survival from birth to the end of hibernation was 31%, comparable with indirect estimates for free-living watersnakes.4. Consistent with the‘bigger is better’ hypothesis, larger neonates and neonates heavier relative to their body length were more likely to survive both the pre-hibernation and hibernation periods.5. Survival in the pre-hibernation period also decreased with the duration of that period and varied among years.6. Survival during hibernation was higher in warmer winters. Mass change prior to hibernation did not affect survival during hibernation.7. These results suggest that an optimal reproductive strategy should exist for female watersnakes, producing a‘consensus’ among females on the optimal size for offspring. This expectation stands in stark contrast to the pronounced variation in offspring size observed both within and among litters.Journal of Animal Ecology(2005) doi: 10.1111/j.1365-2656.2005.00919.x [ABSTRACT FROM AUTHOR]

Seasonal variations in spermatozoa numbers and in sperm motility along the vas deferens in Crotalus durissus terrificus from southeastern Brazil were analyzed. Our data demonstrate storage and motility of the spermatozoa along the vas deferens throughout the year. This is characteristic of a postnuptial reproductive cycle, usually found in snakes living in temperate climates. We describe similarities in reproductive cycle patterns found in the tropical nonhibernator C. durissus terrificus and in hibernator snakes from temperate zones. Our results show that in C. durissus terrificus, a significant difference in spermatozoa counts occurs between winter and summer. Higher numbers of spermatozoa in summer and autumn, due to intense spermiogenesis, coincides with the mating season in autumn. These data indicate that after spermiogenesis in summer, the males combine the peak of sperm storage to the period females are attractive. Mating, however, is not linked to ovulation, and the sperm is stored in the females during winter until fertilization occurs in spring. In the males, after mating, spermatozoon counts low. In spring, they gradually increase, turning again the highest in summer and autumn. During spermiogenesis in the convoluted vas deferens, spermatozoa gain motility, enhancing their performance along their way towards the distal portion. [Copyright &y& Elsevier]

In many species the high energetic demands of reproduction induce a negative energy balance, and thus females must rely on tissue catabolism to complete the reproductive process. Previous works have shown that both fat and protein are energy resources during prolonged fasting in vertebrates. While many ecological studies on energy costs of reproduction have focused on variations in fat stores, the impact of protein investment on the female has not been thoroughly investigated. Notably, as there is no specialized storage form for proteins, intense catabolism is likely to entail structural (musculature) loss that may compromise maternal physical performance after reproduction. Measurements on captive rainbow boas (Epicrates cenchria maurus) confirm that reproducing females undergo significant protein catabolism (as indicated by elevated plasma uric acid levels) and show considerable musculature loss during gestation (as detected by reduced width of the epaxial muscles). Protein mobilization entailed a significant functional loss that was illustrated by decrements in tests of strength and constriction after parturition. In wild situations, such effects are likely to decrease the snakes’ ability to forage and apprehend prey. Hence, the time period needed to recover from reproduction can be extended not only because the female must compensate losses of both fat stores and functional muscle, but also because the ability to do so may be compromised. Performance alteration is likely to be of equal or greater importance than reduced energy stores in the physiological mediation of elevated post-reproduction mortality rates and infrequent reproductive bouts (e.g. biannual or triannual), two common ecological traits of female snakes. [ABSTRACT FROM AUTHOR]

Body reserves play a major role in several aspects of vertebrate biology. Accurate identification and quantification of body reserves constitute a useful contribution to the better understanding of the energetic costs of reproduction and the implication of food availability in life history traits of organisms. In this study, lipid content in fat bodies, liver and muscle of the viperine snake ( Natrix maura) were measured along an active season. Samples were collected monthly from a natural population of the Ebro Delta Natural Park (NE Spain). This methodology pointed out that lipids stored in fat bodies were the main energetic source during reproduction. In addition, lipids stored in liver appeared to be critical for vitellogenesis, while lipids stored in muscle turned out to be a supplementary energetic resource to fuel reproductive effort. Relationships between changes in body reserves and prey availability in canals of the Ebro Delta were also considered. In males, lipid reserves presented a positive correlation with food availability. On the contrary, lipid reserves in female viperine snakes decreased during vitellogenesis even though food availability increased in this period, which suggests a quick transfer of body lipids to clutch. In April, when rice fields of the Ebro Delta were dry and aquatic prey was scarce for viperine snakes, males and females presented a lower lipid content in fat bodies, liver and muscle than they did in other months, showing a clear link between prey availability and body reserves during food shortage. Thus, patterns of variation in fat levels indicated that Natrix maura is a capital breeder since it acquires resources in advance and stores them until they are invested during the reproductive period. Nevertheless, the shortage in April forces Natrix maura to turn into a facultative income breeder to fuel vitellogenesis. Finally, fat reserves in body components were compared with an estimate of body condition calculated by the residuals from the regression of body mass on body length. In male viperine snakes, the estimate of body condition was correlated with fat levels, revealing that this index is useful to measure condition in living individuals. On the contrary, body condition in females was not correlated with fat levels, which suggests that it is not appropriate to infer condition in female viperine snakes since it depends on the reproductive status of the individuals. [ABSTRACT FROM AUTHOR]

Snakes of both sexes display remarkable flexibility and diversity in their reproductive tactics. Many features of reproduction in female snakes (such as reproductive mode and frequency, seasonality and multiple mating) allow flexible maternal control. For example, females can manipulate not only the genotypes of their offspring (through mate choice or enhanced sperm competition) but also the phenotypes of their offspring (through allocation 'decisions', behavioural and physiological thermoregulation, and nest-site selection). Reliance on stored energy ('capital') to fuel breeding results in low frequencies of female reproduction and, in extreme cases, semelparity. A sophisticated vomeronasal system not only allows male snakes to locate reproductive females by following scent trails, but also facilitates pheromonally mediated mate choice by males. Male-male rivalry takes diverse forms, including female mimicry and mate guarding; combat bouts impose strong selection for large body size in males of some species. Intraspecific (geographical) variation and phenotypic plasticity in a wide array of reproductive traits (offspring size and number; reproductive frequency; incidence of multiple mating; male tactics such as mate guarding and combat; mate choice criteria) provide exceptional opportunities for future studies. [ABSTRACT FROM AUTHOR]

Reproduction may involve profound modifications to behaviors such as feeding, antipredator tactics, and thermoregulation. Such shifts have generally been interpreted as direct consequences of reproduction but may instead be secondary effects of reproduction-associated changes in other traits such as habitat use. We quantified behaviors of red-sided garter snakes (Thamnophis sirtalis parietalis) courting and mating at a communal den, and also of postreproductive snakes dispersing from the same den. Snakes at the den actively courted, did not feed, tolerated close approach by humans, and did not retaliate (bite) when seized by us. Dispersing snakes did not court, fed, fled from our approach, and bit when seized. Snakes of both groups were then transferred to outdoor arenas and retested. Courtship vigor by males, and attractiveness of females, had declined but not disappeared for the dispersing snakes. Snakes of both groups ate readily, showing that reproduction-associated anorexia was a facultative response to lack of prey in the den. Body temperature regimes were also similar in the two groups of snakes. Overall, many of the characteristic behavioral changes associated with reproduction were responses to features of the den environment (e.g., presence of sexual partners, lack of food) rather than to reproduction per se. The shift in antipredator responses, however, may reflect a neural or endocrine “switch,” suggesting that the link between reproduction and other behaviors involves a diversity of proximate mechanisms. [ABSTRACT FROM AUTHOR]

Examines the potential costs of reproduction of female aspic vipers Vipera aspis. Depletion of body reserves; Correlation between survival rates and postreproductive mass recovery; Influence of body reserves on lifetime reproductive success.

Reproductive traits and the trade-offs among these traits were examined in two venomous terrestrial elapid snakes, the Australian lowland copperhead, Austrelaps superbus, and the Australian highland copperhead, Austrelaps ramsayi. Sampling was difficult, so gravid females had to be held in captivity for up to several months prior to parturition. Analyses showed that captivity affected the time of parturition and maternal body condition, but it had no apparent effect on offspring traits. The results were corroborated by conducting partial follicular ablations in gravid A. superbus with fully yolked follicles. While these females gave birth earlier than unmanipulated females, offspring size was highly correlated with follicular size at the time of ablation and fell within the size range observed in the other females. This suggests that offspring size is fixed by the time follicles are fully yolked. Among unmanipulated females, reproductive traits were similar in A. superbus and A. ramsayi, but relationships among the traits differed. In the A. superbus sample, the trade-off between litter size and offspring size only became apparent after partial correlations, presumably because spring foraging obscured this relationship. In the A. ramsayi sample, however, the trade-off between litter size and offspring size was very pronounced. At this locality, there was no evidence of spring foraging, and snakes had fully developed follicles before or soon after they emerged from hibernation. This reduces the temporal separation between the times when litter size and offspring size are fixed and may allow greater control over the distribution of resources to offspring as a function of litter size.Les caractéristiques reliées à la reproduction et les compromis entre ces caractéristiques ont été étudiés chez des élapidés terrestres venimeux Austrelaps superbus et Austrelaps ramsayi. L'échantillonnage de ces animaux est difficile, ce qui m'a obligé à garder des femelles gravides en captivité pour plusieurs mois avant la mise bas. Les analyses ont démontré que la captivité affecte le moment de la mise bas et la condition physique des mères, mais elle n'a pas d'effet apparent sur les caractéristiques de la progéniture. Ces résultats ont été corroborés par des ablations folliculaires partielles chez des femelles gravides d'A. superbus à follicules pleins de vitellus. Bien que ces femelles aient mis bas avant les femelles qui n'ont pas été manipulées, il y avait une forte corrélation entre la taille des rejetons et la taille des follicules au moment de l'ablation et la taille des rejetons était du même ordre que celle des rejetons des autres femelles. Cela laisse croire que la taille de la progéniture est déterminée avant que les follicules ne soient remplis de vitellus. Chez les femelles non manipulées, les caractéristiques reliées à la reproduction étaient les mêmes chez les deux espèces, mais la relation entre les caractéristiques différait. Dans l'échantillon d'A. superbus, le compromis entre le nombre de rejetons et leur taille n'est devenu apparent qu'après examen des corrélations partielles, probablement parce que la quête de nourriture au printemps masque la relation. Dans l'échantillon d'A. ramsayi, cependant, le compromis entre le nombre de rejetons et leur taille s'est avéré bien évident. Au site d'étude, rien ne nous permet de croire qu'il y ait quête de nourriture au printemps et les follicules des serpents étaient complètement développés avant ou peu après la fin de l'hibernation. Cela réduit l'intervalle de temps entre le moment où le nombre de rejetons est déterminé et celui où la taille des rejetons est établie, ce qui permet peut-être une meilleure gestion de la répartition des ressources parmi les rejetons en fonction de leur nombre dans la portée.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the larval bloom of oviparous sponge Cliona viridis in rocky communities of the Blanes littoral in northeastern Spain. Discussion on sexual reproduction in sponges; Methodology of the study; Results of the study.

Studies were continued to investigate the ability of secondary metabolites sequestered in Antarctic sponges to cause feeding deterrent responses (tube foot retractions) in a common predator of Aritarctic sponges, the sea star Perknaster fuscus. Lipophilic (dichloromethane/methanol) and hydrophilic (methanol/water) extracts of 15 new species of Antarctic marine sponges were tested for their ability to induce sustained tubefoot retraction. One additional species, Cinchyra antarctica, was re-tested from a previous study because we discovered a colour morph that was of comparative interest. Employing established protocols, sponge extracts were imbedded in silicone and presented to an extended tube-foot on the tip of a glass rod. Extracts of ten of the 15 new species of sponges (67%) caused significantly longer tube-foot retractions than controls. Among all sponges tested, significant tube-foot retraction activity was primarily associated with dichloromethane/methanol extracts (eleven sponge species or colour morphs), while significant tube-foot retraction activity was less common in response to methanol/water extracts (three sponges species or colour morphs). Both lipophilic and hydrophilic extracts from the sponges C. antarctica (yellow morph) and Scolymastia joubini elicited significant tube-foot retraction activity, suggesting that more than one compound from these speciesmight elicit tube-foot retractions in P. fuscus. Overall these findings lend considerable support to the hypothesis that there has been significant evolutionary selection for chemical defences among Antarctic marine sponges in McMurdo Sound, in contrast to earlier biogeographic selection models that predicted low levels of chemical defences in polar marine invertebrates. [ABSTRACT FROM PUBLISHER]

Features a study which described the reproduction cycles and dependence of different sexual reproduction stages on environmental factors in demosponges species Halisarca dujardini, Myxilla incrustans and Iophon piceus. Methods used; Study area; Results.

Reports on a research conducted in Israel on the mode of sexual reproduction of the sponge species Latrunculiidae. Taxonomic position of the species.

Presents a study which investigates the evolution of reproduction in snakes and lizards. Related studies; Materials and methods; Results; Discussion.

Presents information on a study on the sexual and asexual phases of the reproductive cycle of the sponge Mycale contarenii collected from Porto Cesareo Basin, Apulia, Italy. Methodology of the study; Results and discussion; Conclusion.

Information on Thamnophis Eques Megalops (Northern Mexican Garter- Snake), including information related to its population, habitat and reproduction, is presented.

The article discusses miscellaneous topics on herpetoculture. It presents study suggesting that the ingestion of Byrsonima microphyla fruits by Ameivula abaetensis (A. abaetensis) lizard species may be an important source of water in resting habitat during the dry season, longevity of Crotalus oreganus oreganus rattlesnake at the Splash Education Center and reproduction by Masticophis mentovarius, a neotropical colubrid.

The evolution of snake pregnancy process is poorly studied in live animals. Ultrasonography is a not invasive and easy method that makes it possible to evaluate and determine the reproductive phases and the pregnancy. This study had the objective to describe the pregnancy process of the viviparous snake Epicrates cenchria by means of ultrasound evaluation. [ABSTRACT FROM AUTHOR]

The article presents a study which focuses on the observations of the reproduction of Colobodactylus (C.) dalcyanus which were taken during a herpetological survey in October 15-18, 2005. It mentions that two of the four female C. dalcyanus with eggs in their oviducts were preserved, while the remaining two specimens were kept alive and transferred to the laboratory where they laid eggs. It says that the first female which was found under leaf litter has reacted by moving the body without loosening the curl around the eggs and remained inactive when left in-situ. Moreover, an initial parental care of eggs by C. dalcyanus was suggested by the two records of the behaviors.