Ecology and Animal Biology

Copulation duration is highly variable (0.5–3 h) in the damselfly, Ceriagrion tenellum (Coenagrionidae). Using laboratory experiments, we tested four adaptive hypotheses to explain this variation: the effect of time constraints, in-copula mate guarding, sperm displacement and cryptic female choice. Copulation duration was negatively correlated with time of day, as predicted by the first two hypotheses, and positively correlated with male density, as predicted by the mate-guarding hypothesis. Males prolonged copulation in response to the volume of sperm stored by females, suggesting they were able to detect and quantify the amount of sperm stored. This behaviour is not explained by mate guarding or time constraint effects. Males removed all the sperm from the bursa copulatrix in just 10 min. Our results also suggest that, because the duct is too narrow to allow male genitalia to enter, males do not remove spermathecal sperm. Therefore, direct sperm removal could not explain long copulations. Prolonged copulations could also have evolved as a result of cryptic female choice if they increase male fertilization success by female-mediated processes. Our results support this idea: male fertilization success was greater after long copulations. Apparently, male copulatory behaviour elicits female responses that increase male fertilization success.

Population ecology is concerned with estimates of the composition and size of populations and the processes that determine their dynamics. To this aim, population ecologists must track wild animals over their lifetimes, and this task is only possible if animals are marked individually and can be recaptured afterwards.

Longevity in the laboratory was measured for 1071 individuals of Ischnura graellsii, 75 of/. pumilio, 127 of Coenagrion scitulum and 41 of Enallagma cyathigerum. Individuals were maintained in 5 insectaries (50x50x50 cm) with numerous perching substrates, and adults of Drosophila were added as food. Results indicate that males do not live as long as females, in all spp., although the difference was not significant for C. scitulum. Most/. graellsii adults were obtained from the offspring of 33 laboratory crosses. In this sp.

During the last fifty years ecology has matured as a scientific discipline. In this paper I analyse the temporal development of the paradigm based on physical systems (the ecosystem paradigm), and the evolutionary ecology paradigm. I first analyse the contents of 61 textbooks to calculate the relative importance of ecosystem and evolutionary ecology in the training of new generations of ecologists.

Three communities of Calopteryx have been studied from 1985 to 1987 at Galicia (NW of Spain) by markingrecapture techniques. A total of 1275 adults of three species {haemorrhoidalis, virgo and xanthostoma) were marked. The proportion of recaptures was 34%(1985) and 48%(1986) in haemorrhoidalis, 54%(1986) in virgo and 38%(1987) in xanthostoma.

Abstract The European pond turtle (Emys orbicularis) is threatened and in decline in several regions of its natural range, due to habitat loss combined with population fragmentation. In this work, we have focused our efforts on studying the genetic diversity and structure of Iberian populations with a fine-scale sampling (254 turtles in 10 populations) and a representation from North Africa and Balearic island populations.

Abstract We studied egg production and the occurrence of adaptive superparasitism in Anaphes nitens, an egg parasitoid of the Eucalyptus snout beetle Gonipterus scutellatus. First, we determined whether A. nitens females were synovigenic or pro-ovigenic. Newly emerged females were allowed to lay eggs alone during 3 days on six fresh egg capsules. A first group of females (n= 25) were killed by freezing and the remaining females (n= 21) were maintained during two extra days with food, but without hosts.

Morphological variability was studied in laboratory-reared adults. The size of the postocular spots and the antehumeral stripes was surveyed in 1064 F1 individuals, as was the size of the black dorsal spot of the eighth abdominal segment in 994 F, and F2 females. Total body length was measured in 884 6 and I404 9 from FI to F4 generations. Results indicated significant differences among families in all morphological characters, suggesting the existence of genetic variability.

Resumen Las especies que contienen poblaciones con diferentes modos de reproducción, ofrecen las mejores oportunidades para estudiar la transición entre ambas estrategias. Salamandra salamandra es una de las dos especies dentro del clado Salamandra-Lyciasalamandra, la cual muestra simultáneamente los dos modos de reproducción. A lo largo de la distribución de S.

Natural hybridization is a common process in plants, but in most groups of animals, diversification over time is interpreted as a series of branching events, in which hybridization occurs rarely (Harrison, 1993). In some cases, a hybrid zone could arise as a consequence of secondary contact between two populations that have evolved in sympatry (Barton & Hewitt, 1989).

Methods We reanalysed large samples of polychromatic damselflies obtained by Cordero and coworkers (Cordero 1992; Andrés 1998; Cordero & Egido 1998; Cordero et al. 1998; Cordero & Andrés 1999), including four populations of Ischnura graellsii, one of I. elegans, one of I. pumilio and one of Ceriagrion tenellum (studied over 2 years). All samples were obtained during mark–release–recapture studies and are based on ca. 1 month of field work per site.

Species that exhibit colour polymorphism, the simultaneous occurrence of two or more discrete phenotypes with a genetic basis, are ideal for studying the microevolutionary forces that maintain genetic variation in nature. One very intriguing type of genetically determined polymorphism is the co-existence of several discrete morphs within only the male, or within only the female, sex. These morphs typically differ in body coloration and sometimes behaviour, with one morph often resembling the opposite sex.

Mating in Gonipterus scutellatus is very long and lasts on average 6.98±0.49 hr. This could be interpreted as a mechanism of male guarding, but males neither increase copulation duration nor ejaculate volume when sperm competition risk increases. We studied paternity patterns using RAPDs, and the influence of multiple matings on fertility, fecundity and sperm supply.

Abstract The Eucalyptus snout beetle, Gonipterus scutellatus, was first detected in NW Spain in 1991, in the area with the largest European eucalypt plantations. Feeding preferences in the field and the effect of three species of Eucalyptus on larval development, survival, and adult fertility were studied. It was estimated that individuals of G. scutellatus consume 1.2–1.7 g of fresh biomass in Eucalyptus cinerea and E. globulus during their development.

Several spp. of odonates have been the subject of sexual selection studies. In nonterritorial species most variance in lifetime mating success (LMS) is accounted for by lifespan and specially by the number of visits, and random factors (like rainy weather) can have strong effect on reproductive success. Here we present the study of 2 natural populations of/, graellsii by marking-recapture methods. Our results show that â mating success is related to body size, mobility and handling damage, but not to fluctuating asymmetry.

Abstract. The Eucalyptus weevil, Gonipterus scutellatus, shows a complex copulation behaviour whose duration is extremely variable, from less than one hour to more than two days. We tested different hypotheses that could explain the adaptive significance of prolonged copulations. Male genitalia is unable to reach to the interior of the espermatheca of the female, where the sperm of previous matings are stored, so prolonged copulation does not function to remove rivals' sperm.

Summary 1. Age-dependent increases in mortality have been documented in a variety of species of insect under laboratory conditions. However, while strong statistical evidence has been presented for senescence in vertebrate populations in the wild, we know little about the rate and shape of senescence in wild populations of insects.

The scaling of body proportions in/. graellsii is analyzed as body mass in dried specimens and linear dimensions are measured from photographic slides. Results indicate that abdomen mass shows positive allometry with body mass in both sexes, and thorax mass also does so in males. Wing area increases with body mass as expected from geometric similarity, but head width shows negative allometry with body length in both sexes.

Abstract: Rearing damselflies under laboratory conditions is a promising means of solving a variety of biological questions. Therefore, in order to improve the success of future researchers we felt the need to indicate potential difficulties in carrying out rearing experiments. Laboratory crosses were obtained using virgin animals originating from natural populations in Belgium and Spain. Resulting offspring was maintained, under laboratory conditions, in small aquaria until emergence and in insectaries as adults.