Capra Pyrenaica Research Articles

Sustainable Development in Spanish Listed Companies: A Strategic Approach

AbstractCompanies should be interested in implementing corporate social responsibility (CSR) practices not only for ethical reasons, but also for their potential profits. Considering the need to confirm this relationship more thoroughly, this research is based on the only stock market index in Spain which is an objective indicator of best business practices. The purpose of this study is to find out whether being listed in the FTSE4Good IBEX explains a different ulterior financial performance. To this end, the potential accounting and stock market differences between two groups of companies listed in the Spanish IBEX are analysed: those classified as responsible due to their inclusion in the responsible company index and those companies which, as they are not in it, do not receive this denomination. The study, conducted according to the CSR strategic approach, covers 2008–2013. Its outcomes confirm the presence of significant differences between the two groups. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment

Molecular Analyses Reveal Unexpected Genetic Structure in Iberian Ibex Populations.

BackgroundGenetic differentiation in historically connected populations could be the result of genetic drift or adaptation, two processes that imply a need for differing strategies in population management. The aim of our study was to use neutral genetic markers to characterize C. pyrenaica populations genetically and examine results in terms of (i) demographic history, (ii) subspecific classification and (iii) the implications for the management of Iberian ibex.Methodology/Principal FindingsWe used 30 neutral microsatellite markers from 333 Iberian ibex to explore genetic diversity in the three main Iberian ibex populations in Spain corresponding to the two persisting subspecies (victoria and hispanica). Our molecular analyses detected recent genetic bottlenecks in all the studied populations, a finding that coincides with the documented demographic decline in C. pyrenaica in recent decades. Genetic divergence between the two C. pyrenaica subspecies (hispanica and victoriae) was substantial (FST between 0.39 and 0.47). Unexpectedly, we found similarly high genetic differentiation between two populations (Sierra Nevada and Maestrazgo) belonging to the subspecies hispanica. The genetic pattern identified in our study could be the result of strong genetic drift due to the severe genetic bottlenecks in the studied populations, caused in turn by the progressive destruction of natural habitat, disease epidemics and/or uncontrolled hunting.ConclusionsPrevious Capra pyrenaica conservation decision-making was based on the clear distinction between the two subspecies (victoriae and hispanica); yet our paper raises questions about the usefulness for conservation plans of the distinction between these subspecies.

Leopards as taphonomic agents in the Iberian Pleistocene, the case of Racó del Duc (Valencia, Spain)

Bone accumulations created by carnivores during the Pleistocene have been largely associated with the action of cave hyenas (Crocuta spelaea Golfüss, 1823), identified all over Europe. Yet in recent years it has been shown that leopards (Panthera pardus Linnaeus, 1758) played a role in the creation of sites in the Iberian Peninsula. In this study we present the taphonomic study of the bone accumulation of the Pre-Solutrean level at the Racó del Duc Cave (south of the province of Valencia), where the dominant species (Capra pyrenaica Schinz, 1838) has been accumulated by leopards. Together with new data and other references taken from the bibliography, we have summarised the main taphonomic characteristics of the sites accumulated by leopards. The predator-prey relationship has also been analysed and it has shown that during the Pleistocene, leopards in the Iberian Peninsula were specialised in catching goats, showing similar behaviour to that of snow leopards. Said specialisation may have been due to the occupation of caves in steep areas where rupicolous fauna predominated.

Pleistocene cave hyenas in the Iberian Peninsula: New insights from Los Aprendices cave (Moncayo, Zaragoza

Instituto Universitario de Investigacion en Ciencias Ambientales de Aragon, Universidad de Zaragoza, Espana

Monitoring of pseudotuberculosis in an Italian Population of Alpine Chamois: Preliminary Results

Caseous lymphadenitis (CLA) of sheep and goats is a chronic and often sub-clinical disease, with high prevalence in different parts of the world, which can caused significant economic losses for farmers. The causative agent is Corynebacterium pseudotuberculosis that primarily infects domestic small ruminants, but it has been isolated also in wildlife such as pronghorns (Antilocapra americana) and elk (Cervus elaphus canadensis). Furthermore, a recent research has demonstrated a maintenance of the infection on an endemic level in a Spanish ibex (Capra pyrenaica hispanica) population after an outbreak with high morbidity and mortality. The typical clinical manifestation is lymph node abscess that may fistulize and discharge pus contaminating the environment where can survive for months in faeces, fomites, and soil. Infected subjects with the sub-clinical form can also shed bacteria through respiratory tract and mechanical vectors such as flies. Human infection is a rare event. Wildlife-livestock interfaces are dynamic and bidirectional and pathogens could be transmitted freely within and between the two species. The study area is the Alpine hunting district located in Vercelli province (formerly named C.A. VC1). The study was carried out during 2016 hunting season, between September and December and performed on hunted chamois. A macroscopic examination of each carcass has been conducted at the Control Centre, where each hunter had to bring the chamois after culling for the control by a veterinarian. Hunters collected post-mortem-blood samples via jugular or heart clot from their own bag and leaded up to the Control Centre where serum was obtained by centrifugation and stored at -20°C until further processing. A commercial enzyme-linked immunosorbent assay (ELISA) kit (ELITEST CLA, HYPHEN BioMed, France) has been used to detect antibodies (IgG) anti-PLD. Results have been expressed as OD after reading the plates at 450 nm in an ELISA microplate reader. The aim of this monitoring is to confirm the circulation of C. pseudotuberculosis in the chamois population as suspected on the basis of the finding of several chamois with characteristic lesions during previous hunting seasons and to identify risk factors for the infection and the development of clinical signs of disease. 196 chamois have been hunted in 2016 hunting season, a total of 34 sera have been processed (1 kid, 7 yearlings, 17 adult males, 9 adult females) showing a seroprevalence of 8.82% (c.i. 95% 0.0-18.26). One yearling female and two adult females resulted seropositive; at the macroscopic examination the two adults had showed typical lymph node abscesses in abdominal cavity and the oldest was underweight and presented typical dermatophilosis lesions. Furthermore, a 4-year-old male showed a grey zone OD. The results of this first year survey on the territory are to be considered as preliminary, the starting point for a data collection that can become a historical series that could give useful management guidance in the near future. In spite of this, it can be safely stated that the first results obtained confirm the circulation of C. pseudotuberculosis, together with the pathological and bacteriological diagnoses of previous years. The fact that a yearling seropositive has been found without any lesions found is evidence of the current circulation of the pathogen as this subject has come into contact with the infection during the previous year.

Does Sarcoptes scabiei synchronize its breeding cycle with that of the Iberian Ibex, Capra pyrenaica?

ABSTRACTWe have analysed five samples from the skin of 368 Iberian ibexes from Sierra Nevada Natural Space (southern Spain) in order to characterize the age structure of the Sarcoptes scabiei metapopulation affecting this host population and, particularly, to search for possible reproductive peaks of the parasite. Monthly mean mite density and number of larvae peaked in November, coinciding with the rutting season of its host, when the size of ibex mixed groups becomes larger. On the other hand, monthly number of nymphs differed significantly, reaching higher values in May (coinciding with the peak of parturitions), August and November. Our results suggest that (i) there is some extent of synchronization between the breeding cycles of both the host and the parasite and (ii) nymphs could play an important role in the mite transmission to offspring. We discuss the potential role of sexual hormones in such increase of larvae and therefore in mite numbers.

Parasite load in the Iberian ibex, Capra pyrenaica victoriae

Parasitic infections in the Iberian ibex are common, serious and well documented. Most studies, however, focus on the subspecies Capra pyrenaica hispanica, found in the south and east of the Iberian peninsula, and few studies have investigated the subspecies Capra pyrenaica victoriae in the centre of the peninsula. Here we add to the information about C. p. victoriae, analyzing samples of this subspecies in the National Park of Sierra de Guadarrama. We found parasites in 97% of samples and identified a total of 11 helminth taxa. The most abundant genus in the analysis was Muellerius. Despite the frequency of parasites, the general health of the population seemed good.

Wide exposure to Coxiella burnetii in ruminant and feline species living in a natural environment: zoonoses in a human-livestock-wildlife interface.

Assessment of the role of wild and domestic hosts as potential reservoirs of misdiagnosed zoonoses, such as Q fever by Coxiella burnetii, is an important public health issue today both for wildlife conservation and management of disease in human-livestock-wildlife interface. This study used ELISA, an indirect antibody, to research (2003-2013) C. burnetii infection in seven free-living wild and domestic ruminant species and in European wildcats (Felis silvestris). The animals studied were 0 European wildcats, 21 Spanish ibex (Capra pyrenaica), 314 red deer (Cervus elaphus), 556 fallow deer (Dama dama), 211 European mouflon (Ovis aries musimon), eight roe deer (Capreolus capreolus), 407 bovines (Bos taurus) and 3739 sheep (Ovis aries). All the animals shared the same habitat in the Serranía de Cuenca Natural Park (Castile-La Mancha, Spain). The study area is an example of human-domestic-wildlife interface where people and domestic animals live in close proximity to wildlife. Observed C. burnetii seropositive frequencies were: 33·3% European wildcats, 23·8% Spanish ibex, 22·5% domestic sheep 1·5% red deer, 1·4% European mouflon, 0·24% cattle, 0·18% fallow deer and 0% roe deer. The study found a wide C. burnetii prevalence of previous and present exposure in wild and domestic ruminant hosts in the Serranía de Cuenca Natural Park and reports the first evidence of C. burnetii exposure in free-living European wildcats.

Influence of seasonality and stimulus of oestrous does in bucks’ aggressiveness

Aggressiveness is directly related to testosterone concentration, which varies with seasons and in response to female stimulation. The aim was to determine if the frequency and pattern of agonistic interactions between bucks varies seasonally and in response to oestrous female stimulation. In the first study we characterized the pattern of agonistic interactions during feeding throughout a whole year in groups of Iberian ibex bucks; and in the second study, we determined the influence of oestrous does on the frequencies of agonistic behaviours between Gabon bucks in different seasons. In Iberian ibex bucks, the frequency of agonistic behaviours was maximum in summer and testosterone concentration in late autumn. In Gabon bucks, total agonistic interactions increased in bucks stimulated by females in late summer and autumn. In late autumn there were more interactions without physical contact in stimulated than in isolated bucks. Aggressiveness in bucks varied along the year, but the seasonal pattern was related to the context in which behaviours were recorded. Stimulation with oestrous females induced an increase of aggressiveness during the breeding season. At least in the conditions of these studies, testosterone concentrations seemed not to be the main influence on the frequency in which aggressive behaviour was displayed.

Favourableness and connectivity of a Western Iberian landscape for the reintroduction of the iconic Iberian ibexCapra pyrenaica

AbstractTraditional land use practices declined throughout many of Europe's rural landscapes during the 20th century. Rewilding (i.e. restoring ecosystem functioning with minimal human intervention) is being pursued in many areas, and restocking or reintroduction of key species is often part of the rewilding strategy. Such programmes require ecological information about the target areas but this is not always available. Using the example of the Iberian ibexCapra pyrenaicawithin the Rewilding Europe framework we address the following questions: (1) Are there areas in Western Iberia that are environmentally favourable for reintroduction of the species? (2) If so, are these areas well connected with each other? (3) Which of these areas favour the establishment and expansion of a viable population of Iberian ibex in a reintroduction programme? We modelled environmental favourableness for the species in the Iberian Peninsula using a logistic regression with a forward–backward stepwise procedure, and assessed landscape connectivity using a graph analytical approach after downscaling the model to the Western Iberia region. Our results indicate that several habitat patches in the study area present favourable environmental conditions for reintroduction of the Iberian ibex. Overall, most of the habitat connectivity was concentrated in northern and central patches. We highlight the potential and practical application of the analytical protocol used, for successful integration of species distribution modelling and landscape connectivity in the design of broad-scale reintroduction and recovery programmes.

Sarcoptes scabiei infestation does not alter the stability of ectoparasite communities.

BackgroundThe host represents a heterogeneous ecosystem where multiple parasite species co-occur and interact with each other for space and resources. Although these interactions may rule the features of an infracommunity and may shape the infracommunity response to external perturbations, the resilience of ectoparasite communities to new infestations remains poorly explored.MethodsWe analysed the composition of the ectoparasite communities found on 214 individual Iberian ibexes (Capra pyrenaica) inhabiting the Sierra Nevada Natural Space, southern Spain. Using classification and regression trees, we explored how the presence of Sarcoptes scabiei (a highly contagious mite), the off-host environment and the host sex govern the prevalence and abundance of lice and ticks. Null model analysis was applied to assess the impact of S. scabiei on the structure of the ectoparasite communities.ResultsOur results suggest that S. scabiei infestation acts in tandem with off-host environment and host sex to define the prevalence and abundance of lice and ticks. We also provided evidence for differences in species co-occurrence only at the early stages of S. scabiei infestation. Regarding species diversity, we recorded that ectoparasite communities in scabietic ibexes reached a high richness faster than those in healthy individuals.ConclusionsEven though we show that ectoparasite burden is correlated with S. scabiei infestation, off-host environment and host sex, the species response to S. scabiei infestation and climate seem to be highly variable and influenced by ectoparasite life-history traits. Ectoparasite communities also appear resilient to perturbations which is in agreement with what was previously reported for endoparasites. Future refinement of sample collection and the incorporation of ecological and epidemiological-related variables may allow us to establish causal effects and deepen the knowledge about the mechanisms and consequences of ectoparasite interactions.

Effect of shortening the prefreezing equilibration time with glycerol on the quality of chamois (Rupicapra pyrenaica), ibex (Capra pyrenaica), mouflon (Ovis musimon) and aoudad (Ammotragus lervia) ejaculates

The present study reports the effect of shortening the prefreezing equilibration time with glycerol on the quality of frozen-thawed ejaculated sperm from four Mediterranean mountain ungulates: Cantabrian chamois (Rupicapra pyrenaica), Iberian ibex (Capra pyrenaica), mouflon (Ovis musimon) and aoudad (Ammotragus lervia). Ejaculated sperm from these species were divided into two aliquots. One was diluted with either a Tris-citric acid-glucose based medium (TCG-glycerol; for chamois and ibex sperm) or a Tris-TES-glucose-based medium (TTG-glycerol; for mouflon and aoudad sperm), and maintained at 5°C for 3h prior to freezing. The other aliquot was diluted with either TCG (chamois and ibex sperm) or TTG (mouflon and aoudad sperm) and maintained at 5°C for 1h before adding glycerol (final concentration 5%). After a 15min equilibration period in the presence of glycerol, the samples were frozen. For the ibex, there was enhanced (P<0.05) sperm viability and acrosome integrity after the 3h as compared with the 15min equilibration time. For the chamois, subjective sperm motility and cell membrane functional integrity were less (P<0.05) following 15min of equilibration. In the mouflon, progressive sperm motility and acrosome integrity was less (P<0.05) when the equilibration time was reduced to 15min. For the aoudad, the majority of sperm variables measured were more desirable after the 3h equilibration time. The freezing-thawing processes reduced the sperm head size in all the species studied; however, the equilibration time further affected the frozen-thawed sperm head variables in a species-dependent fashion. While the equilibration time for chamois sperm might be shortened, this appears not to be the case for all ungulates.

The role of wild ruminants as reservoirs of Besnoitia besnoiti infection in cattle

Bovine besnoitiosis, a parasitic disease caused by Besnoitia besnoiti, has been reported mainly in beef cattle raised under extensive pastoral systems and is considered to be re-emerging in Western Europe. Horizontal transmission probably occurs either by means of blood sucking arthropods or as a consequence of direct contact between infected and non-infected cattle. However, the role that wild ruminants (e.g., red deer (Cervus elaphus) and roe deer (Capreolus capreolus)) may play in the parasite life cycle as putative reservoirs remains elusive. Thus, we investigated the presence of Besnoitia spp. infection in 2608 wild ruminants located in areas where bovine besnoitiosis is present and identified the Besnoitia species detected. First, a serosurvey was conducted in red deer (n=309), roe deer (n=417), Pyrenean chamois (Rupicapra p. pyrenaica, n=383) and Iberian wild goat (Capra pyrenaica hispanica, n=288) from two areas of Aragon, northeastern Spain, where bovine besnoitiosis is endemic. Second, red deer (n=820), roe deer (n=37), fallow deer (Dama dama, n=166), Iberian wild goat (n=86) and European mouflon (Ovis orientalis musimon, n=102) from southwestern Spain, where new outbreaks have recently been reported, were also sampled. The presence of Besnoitia spp.-specific antibodies was confirmed by western blot in one red deer and one roe deer from the Pyrenees, and Besnoitia spp. DNA was detected by ITS1-PCR in the seropositive red deer. Besnoitia genotyping based on 6 microsatellite (MS) analyses was carried out in red deer samples and compared with B. besnoiti genotypes from 7 in vitro isolates and 3 infected bovines, B. tarandi (1 isolate) and B. bennetti (from tissues of an infected donkey) for Besnoitia spp. assignation. Multilocus MS analysis of B. besnoiti, B. tarandi and B. bennetti showed specific genotypes for each species. A restricted genetic diversity with two genotypes by variation in a unique MS marker was revealed among the 7 B. besnoiti isolates. Incomplete Besnoitia spp. genotype of 3 MS markers from red deer samples entirely matched the B. besnoiti genotypes. Accordingly, this work gives clues for the presence of B. besnoiti infection in red deer from Western Europe. Further molecular genotyping is needed to confirm that red deer may act as an intermediate host of B. besnoiti, although the low prevalences that were found indicate that wild ruminant species do not pose a significant risk of transmitting the infection to cattle.

Not so deserted…paleoecology and human subsistence in Central Iberia (Guadalajara, Spain) around the Last Glacial Maximum

In contrast to the coastal areas of the Iberian Peninsula, the Upper Palaeolithic settlement of central Iberia, dominated by the Spanish plateau, is poorly known. Traditional models assume a total or virtual depopulation of the interior of the Iberian Peninsula during the Last Glacial. In this paper we present a detailed investigation of human-environment interactions through the first zooarchaeological, taphonomic and isotopic study of the key site of Peña Capón, a rock shelter located in the south-eastern foothills of the Central System range that contains a multi-layered deposit dated to marine isotope stage 2 (MIS 2). Analyses of the faunal assemblages of the Proto-Solutrean (3) and Middle Solutrean (2) layers show that human preferentially hunted horse, deer and iberian ibex living in the vicinity of the rock shelter. Isotope geochemistry of the animal remains of Peña Capón provides us with the first detailed intra-tooth multi-proxy analysis for this time period in south-western Europe, providing estimates of climatic conditions, seasonal flucturation of diet, as well as patterns of seasonal mobility. Our results indicate that human presence at Peña Capón was apparently restricted to relatively warm intervals around the LGM or reflects the presence of an ecological refuge, and provide us with evidence of recurrent human presence in the Iberian interior during the Upper Paleolithic prior to the Magdalenian.

Space use of a reintroduced population of Iberian ibex (Capra pyrenaica) in a protected natural area

In Europe, wild ungulates have undergone major expansion and population growth during recent decades. In certain cases, the high density achieved by these populations has led to excessive pressure on the environment, which eventually becomes a limiting factor for the population itself. One of these reintroductions was performed with the Iberian ibex (Capra pyrenaica Schinz, 1838) in the Sierra de Guadarrama National Park (Spain). This reintroduced population was monitored during six field seasons (2000, 2003, 2005, 2007, 2010, and 2014) by direct observation of the animals along transects using the distance sampling method to determine the degree of expansion over the years and the use of different habitats according to different seasons. The abundances obtained for each field season showed a significant increase from 4.16 to 8.65 individuals/km, showing a linear relationship between abundance and extent of the area occupied by the species. We observed that differences between habitat availability and use were significant for all seasons. Our data can be used as an example of the colonization process of a population of wild ungulates and their impact on vegetation to better manage future reintroductions.

Modelling the habitat of a wild ungulate in a semi-arid Mediterranean environment in southwestern Europe: Small cliffs are key predictors of the presence of Iberian wild goat

After a drastic contraction in the species’ range, the Iberian wild goat Capra pyrenaica (Schinz, 1838) has recolonized semi-arid steppe areas where the availability of resources is lower than it is in the species typical habitat. There is a gap in the habitat characteristics that allow the species to survive in an environment that lacks high cliffs and rocky outcrops. We hypothesize that microhabitat characteristics allow the species to find the resources necessary for survival in atypical areas. To test that, we measured several topographic variables (slope, distance to small cliffs and elevation) as well as land use/cover variables (distance to bushes, forests, agriculture, artificial and rivers). To model the habitat in the Middle Ebro Valley, Spain, we used data from 7-yr of monitoring of the species in an averaged-model with Generalized Linear Mixed Model (GLMM-Logit). Distance to small cliffs and distance to bushes explained most of the variance in the model which reflected a fragmented potential habitat. The fragmented structure of the habitat which might act as a metapopulation system, and the spatial configuration of fragments along rivers might act as corridors that favour the dispersal should be taken in consideration in the conservation and management of the species.

Portfolios in the Ibex 35 before and after the Global Financial Crisis

ABSTRACTIn this article, we present an analysis of the effectiveness of various portfolio optimization strategies applied to the stocks included in the Spanish Ibex 35 index, for a period of 14 years, from 2001 until 2014. The period under study includes episodes of volatility and instability in financial markets, incorporating the Global Financial Crisis and the European Sovereign Debt Crisis. This implies a challenge in portfolio optimization strategies since the methodologies are restricted to the assignment of positive weights. We have taken for asset allocation the daily returns with an estimation window equal to 1 year and we hold portfolio assets for another year. This article attempts to influence the discussion over whether the naive diversification proves to be an effective strategy as opposed to portfolio optimization models. For that, we evaluate the out-of-sample performance of 15 strategies for asset allocation in the Ibex 35, before and after of the Global Financial Crisis. Our results suggest that a large number of strategies outperform to the 1/N rule and to the Ibex 35 index in terms of return, Sharpe ratio and lower VaR and CVaR. The mean-variance portfolio of Markowitz with short-sale constraints is the only strategy that renders a Sharpe ratio statistically different from Ibex 35 index in the 2001–2007 and 2008–2014 time periods.

Toxic and Essential Element Concentrations in Iberian Ibex (Capra pyrenaica) from the Sierra Nevada Natural Park (Spain): Reference Intervals in Whole Blood.

Iberian ibex (Capra pyrenaica) blood samples from the Sierra Nevada Natural Park (Spain) were analyzed to establish concentrations of toxic and essential elements. Samples (whole blood from 32 males and 34 females) were taken from wild animals and the concentrations of inorganic elements considered as (1) non-essential and toxic (Pb, Cd and As), (2) essential but potentially toxic (Cu, Zn and Mn) and (3) occasionally beneficial (B, Cr, Al and Ni), as well as (4) essential minerals (Ca, Na, K, P, Mg, S, Co and Fe), were analyzed. The low concentration of Pb and Cd indicated that there is no heavy metal contamination in this geographical area for these elements. The concentration of elements in this ibex population was defined for different genders and ages. Significant differences between genders were only found for Mg and Cu, while significant differences in concentrations of Ca, Cr, Fe, Mn, P, S and Zn were found between ages.

On the population biology of Sarcoptes scabiei infesting Iberian ibex (Capra pyrenaica)

ABSTRACTIn this study, we analysed the Sarcoptes scabiei infrapopulations of 315 Iberian ibex (Capra pyrenaica) by means of skin digestion and differential mite counts. Mean density reached 178.2 mites/cm2 (range: 0.71–4514.29). Although the most frequently affected zones were hosts’ extremities and withers, higher mite densities were obtained from lips and extremities, suggesting that indirect infection through the substrate could also play a role in the disease epidemiology, together with direct transmission. The sex ratio of mites was female-biased (mean: 5.18 ♀♀/♂, range: 0.5–17). Larvae were more frequently found (nearly 50% of specimens) than nymphs, adult females or adult males. Mite density varied significantly between years and decreased with host age. Most of the variance was explained by the year, host sex, weight and kidney fat index (KFI). Taking into account the catabolic nature of the disease, our results suggest that hosts in good body condition could evidence a certain degree of resistance to the disease, which presumably has a genetic basis.

A system dynamics model of the population dynamics of Oestrus sp. (Diptera: Oestridae) infesting Iberian ibex, Capra pyrenaica

We modelled the population biology of Oestrus sp. parasitising the Iberian ibex (Capra pyrenaica), using a system dynamics approach. Levels included in the model were as follows: first-instar larvae, third-instar larvae, pupae and resilient pupae. The values used for flows and auxiliary variables were obtained from the scientific literature, including research on both Oestrus ovis and O. sp.; we assumed that these two species are closely related, both morphologically and from a biological point of view. Simulations provided by our model allowed us to estimate the minimum monthly production of first-instar larvae and thus to establish periodic population dynamics, together with predictions for the number of larval generations. The model predicted 3–4 larval generations per year. The model proved to be very sensitive to minimal changes in a number of variables, especially the first-instar larval production rate. Despite its limitations, this methodology could be a versatile tool for studying the population dynamics of this kind of parasites, and for simulating the effects of control programmes.