Mónica Feriche

Food availability induces geographic variation in reproductive timing of an aquatic oviparous snake (Natrix maura)

The viperine snake Natrix maura is a common water snake, which forages on aquatic prey such as fish and frogs in Western Mediterranean water bodies. Female viperine snakes collected from three populations at the Iberian Peninsula during the vitellogenesis period were compared. Mean clutch size and range, as well as the slope of the regression between body size and clutch size, did not show differences between populations. In contrast, mean size of enlarged follicles of females collected in May from the Ebro Delta proved significantly smaller than those of females from the Matarranya River (50 km far) and the Granada Depression (500 km far). There were no differences in climatic conditions between areas. However, seasonal variation in food availability was significantly different in the Ebro Delta. In this area, the rice fields are dry in early spring as men control the water flow, and prey are not available. This energetic constraint induced female viperine snakes to adjust reproductive timing according to seasonal availability and to delay vitellogenesis for at least one month. By contrast, other Mediterranean populations exhibited a rather high prey availability from early spring (e.g. Matarranya River), females being in good condition in this season and consequently vitellogenesis starting earlier than in the Ebro Delta. This study illustrates a new case of reproductive plasticity in snakes.

Schoolchildren and One of the Most Unpopular Animals: Are They Ready to Protect Snakes?

ABSTRACT For cultural reasons and due to the narrow vision of environmental policy makers, most conservation efforts focus on a few charismatic species and consequently neglect the majority of others under threat; many unpopular species are even killed in large numbers with little concern. Redressing this bias through educational programs is therefore important. Snakes are unpopular animals; they suffer from human harassment in most places and many populations have declined worldwide. Consequently, they provide suitable substrate to better improve conservation education in schoolchildren. Responses to a questionnaire administered to 2,570 schoolchildren (7–14 years old) from 10 countries showed that many children liked snakes and that most of the students wanted to see snakes protected. Such counterintuitive results were supported by the explanations given by the children, notably the reasons they liked or disliked snakes. Previous physical contact with snakes was often associated with snake likeability. We also found strong and expected differences between countries: for instance, where venomous snakes represented a health risk, most children declared to be afraid of snakes. Overall, our results negate the simplistic, and previously unverified, adult view that snakes are necessarily perceived as frightening animals, thereby justifying their persecution. This study provides an encouraging message, suggesting that it is not compulsory to focus on charismatic animals to convince children to protect wildlife.

Sexual Dimorphism and Sexing of Mediterranean Colubrids Based on External Characteristics

Sexual dimorphism was studied in seven colubrid species living in the Mediterranean area of the Iberian Peninsula. Six variables of external morphology were considered: numbers of ventral and subcaudal scales, snout-vent and tail lengths, body and tail surface in a cross section close to the vent, and certain ratios of these variables. To determine which traits enable us to distinguish between the sexes, we used a stepwise discriminant analysis. The ventral and subcaudal scales, because their numbers are fixed at birth, were the best predictors of the sex of a randomly-chosen specimen. Using the number of ventral scales and certain ratios, we correctly identified the sex in all individuals of Elaphe scalaris and Natrix maura, nearly 100% of the individuals of Coluber hippocrepis and Natrix natrix, and almost 95% of Coronella girondica and Macroprotodon cucullatus. The method did not work with Malpolon mon- spessulanus, which is sexually monomorphic in the characteristics used here.

Setting conservation priorities for the Moroccan herpetofauna: the utility of regional red lists.

We assess the national conservation status of the amphibians and reptiles of Morocco by applying the IUCN Red List Criteria at the national level and assess its utility as a planning tool to establish regional priorities for conservation. We rely on the accessory data accompanying regional red lists, mainly distribution range and habitats used by, and threats affecting, species of conservation concern. We also correlated some natural history traits to examine the nature and causes of the risk of extinction. With 13 species of amphibians (31% regionally threatened) and 99 species of reptiles (14% regionally threatened), Morocco is one of the Mediterranean countries with the highest diversity of herpetofauna, mainly because of the high percentage of endemism (amphibians 31%, reptiles 24%). The relative frequencies of threatened species were found to be contingent on both taxonomic group and habitat. The overwhelming importance of the threats of small range and number of habitats used by species is different from the threats to the same species at the global level; this demonstrates the usefulness of national or regional analyses of conservation status for setting conservation priorities. The importance of regional assessment derives from the fact that the boundaries set for conservation management are mainly political rather than biogeographical.

REPRODUCTIVE ECOLOGY OF THE HORSESHOE WHIP SNAKE (COLUBER HIPPOCREPIS) IN THE IBERIAN PENINSULA

-Data on the reproductive ecology of the Horseshoe whip snake (Coluber hippocrepis) are scarce and largely anecdotal in northern Mediterranean populations of this species. Dissections of preserved specimens from the southeast of the Iberian Peninsula, together with field observations, provided information on size at sexual maturity, reproductive and fat body cycling, clutch size, hatching period, and feeding frequency. Males attain sexual maturity at about 500 mm snout-vent length (SVL) and females at 680 mm SVL. As with populations from Northern Africa, males exhibit a prenuptial spermatogenic cycle. The complete reproductive cycle (spermatogenesis, vitellogenesis, mating, shelling, oviposition, incubation, and hatching) occurs within the same calendar year. The northern limit of this spermatogenic cycle also coincides with the northern limit of the distribution of the species. The female reproductive cycle is seasonal, and most sexually mature females reproduce annually. Vitellogenesis is associated with a decline in the fat body level. Oviposition occurs in late June to early July, the mean clutch size is 6.8 eggs, and there is a significant correlation between female size and fecundity. Females feed rarely when gravid. The hatching period begins in late August and lasts to mid-September. Offspring size was 237 to 308 mm SVL, and offspring mass 6.1 to 9.0 g. The reproductive biology of snakes is less well understood than that of any other reptilian group except the crocodilians (Seigel and Ford, 1987). In the Western Palearctic region, most of the studies on reproductive biology of snakes have focused on viperids (Volsoe, 1944; Nilson, 1981; Saint Girons and Duguy, 1992) or colubrids from northern and central Europe (Bourliere and Petter-Rouseaux, 1955; Goodar and Spellerberg, 1980; Naulleau, 1992; Luiselli et al., 1996, 1997), and there are few studies on species inhabiting Mediterranean habitats (but see e reproductive biol gy of snakes is less ll understo d than that of any other r ptilian up except the croc dilians (Seig l and Ford, 7). In the Western Pale rcti region, most of studies on reproductive biology of snakes e focused on viperids (Vols e, 1944; Nilson, 1; Saint Girons and Dug y, 1992) or c lui s from northern and central Europe (BourCheylan et al., 1981; Hailey and Davies, 1987; Agrimi and Luiselli, 1994). Coluber hippocrepis is a long and slender-bodied colubrid, with a total length of up to 1800 mm, and no sexual dimorphism in body size (Feriche et al., 1993). It is found in a variety of warm Mediterranean habitats throughout northern Tunisia and Algeria, most regions of Morocco, and the eastern and southern half of the Iberian Peninsula. The populations inhabiting the Iberian Peninsula have been isolated from the original populations in North Africa since la et al., 1981; Hailey and Davies, 1987; i i and Luiselli, 1 94). hippocrepis is a long and slender-bodl brid, with a tota length of up to 1800 a d no sexual dimorphism in body size i e et al., 1 93). It is found in a variety of editerranean habitats throughout northisia and Algeria, most regions of Mo, a d the eastern and southern half of the i Peninsula. The populations inhabiting 202 This content downloaded from 207.46.13.83 on Sun, 23 Oct 2016 05:04:44 UTC All use subject to http://about.jstor.org/terms REPRODUCTIVE ECOLOGY OF COLUBER HIPPOCREPIS the formation of the Strait of Gibraltar, approximately 5.3 x 106 yr (Busack, 1986; B. Sanchiz, pers. cor.). Although the distribution of the species in southern Europe suggests that males should retain the spermatogenic prenuptial cycle exhibited by the specimens from Morocco (Bons, 1967; Pozuelo, 1974; Saint Girons, 1982), the reproductive biology of the populations from the northern Mediterranean Basin has not

Specialist and generalist species in habitat use: implications for conservation assessment in snakes

Habitat specialization is recorded as one of the central factors that make species vulnerable to extinction. Among snakes, there is considerable variation in this trait, as some species are specialists and others are generalists in habitat use. We have quantified habitat specialization in the snakes of the southern Iberian Peninsula, and compared it with their abundance and IUCN categories. All data were combined for a principal components analysis that discriminated two main groups: three generalist species that live in all types of habitat, and five specialist species that ranged from rather scarce to extremely rare and are found only in unaltered habitats. The three generalist snakes are not threatened and their IUCN category is Least Concern. Three out of the five specialist species are categorized as Near Threatened, Vulnerable, and Endangered at regional or national levels. The other two species are currently considered Not Threatened and we discuss whether they are incorrectly classified. The conservation status of snakes is difficult to evaluate because of their secretive habits and low population densities. We suggest that quantifying habitat specialization may be a useful tool for assessing the conservation status of secretive organisms such as snakes.

Reproductive Ecology of the Montpellier Snake, Malpolon monspessulanus (Colubridae), and Comparison with Other Sympatric Colubrids in the Iberian Peninsula

Abstract 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.

Patterns of tail breakage in the ladder snake (Rhinechis scalaris) reflect differential predation pressure according to body size

Predator-prey interactions are key factors in the evolution of defensive tactics. In snakes, shy organisms from which direct evidence of predator-prey interactions is difficult to obtain, injuries are potential indicators of both the nature and frequency of interactions. We studied the incidence of tail breakage and body scarring in the ladder snake, Rhinechis scalaris, an actively foraging Mediterranean snake, and tested several hypotheses that link body injuries and snake life-history traits, mainly under sexual and ontogenetic aspects. Evidence is presented supporting an ontogenetic shift in the frequency of tail breakage, with the incidence of tail loss increasing as a logistic function of snake size. We relate this finding to the adaptive significance of ontogenetic shifts in dorsal pattern and the reaction of snakes to approaching predators; small individuals are more likely to remain immobile than are medium to large individuals, the former aided by a concealing dorsal pattern with transverse lines, and the latter by a striped pattern. This species exhibited sex differences in body scarring but not in tail breakage, nor did we encounter evidence to suggest that snakes experience multiple tail breaks over time, thus failing to support the sexual difference and multiple tail breakage hypotheses. Moreover, we failed to find a lower frequency of body scarring than tail breakage; hence, our results do not afford evidence that frequency of tail breakage represents an inefficiency of predators in catching or dispatching ophidian prey.

Tail breakage frequency as an indicator of predation risk for the aquatic snake Natrix maura

It is difficult to measure predation risk for secretive animals such as snakes. The frequency of tail breakage has been suggested as a parameter for measuring predation risk in these reptiles. Consequently, we hypothesise that tail breakage frequency is expected to vary intraspecifically between populations submitted to different numbers of predators, probably, to different predation risk. The colubrid snake Natrix maura has adapted to living on fish farms, which are protected from aerial predators by wire mesh, so that these farms provide researchers with a predator-exclusion scenario. We measured tail breakage frequency in this snake on a fish farm and compared the results with data from three populations in natural settings in the Iberian Peninsula under assumed higher predation risk from a complete community of predators. A logistic regression analysis demonstrated that snake body size and predator exclusion affected the probability of tail breakage, while sex had no effect. We found an ontogenetic increase in the frequency of tail breakage, a general pattern in snakes and, notably, marked differences between populations according to predation risk: snakes from the fish farm showed a low frequency of tail breakage (5.1%), whereas snakes from natural habitats, with five-fold more potential predators on average, demonstrated a higher frequency of tail breakage (18.7%). We conclude that tail breakage frequency is a reliable indicator of predation risk in this aquatic snake.

Factors Influencing Schoolchildren's Responses to a Questionnaire in Wildlife Conservation Education

Questionnaires are important tools for assessing attitudes regarding conservation issues. However, they are not easily comparable and their reliability has been insufficiently assessed. We examined factors influencing responses to open- and closed-ended questions about animal conservation to more than 600 schoolchildren (9 years old on average). We analysed the level of understanding, controllable (e.g. sample size) and less controllable factors (e.g. affectivity). Most children responded appropriately to the questions, but subtle changes in the phrasing influenced the answers. Affectivity towards endearing species and spontaneity also influenced the responses whereas small sample sizes (∼50 children) provided relatively stable patterns. Overall, we suggest that standardization of questionnaires administered over large spatial and time scales is needed to accurately assess childrens attitudes towards conservation issues.