Papers by Jacques Van Alphen
Lutra, 2009
In field studies of animal populations, it is often useful to be able to assess the age of an ind... more In field studies of animal populations, it is often useful to be able to assess the age of an individual. In this paper we investigate the use of chin-spots as an indicator of age in pond bats (Myotis dasycneme). During six years of research, from 2002 to 2008, we captured more than 2,500 pond bats. To test whether the chin-spot can be used, we gathered data on chin-spot colour and other indicators of age, such as dental wear, degree of fusion of phalangeal epiphyses and reproductive status. We tested the correlation between chin-spot colour and these indicators of age. We also studied the transformation of these characteristics during bats' life course and therefore between different age classes. We found significant correlations between the colour of the chin-spot and other known age indicators. The results showed a significant relation between colour and the number of days between the first and the last capture. The longer the period between two capture events, the larger the change in colour of the chin-spot. Animals of a known age, captured as juveniles, showed a transformation in coloration from deep purple (class 5) to light-coloured (class 1) over an average time period of two to four years. Most of the juvenile pond bats had a chin-spot coloration in class '4' or '5', most sexual immature animals in class '3' and most mature animals in class '1'. We conclude that the colour of the chin-spot is a reliable predictor of the age class of pond bats.
PAV-bulletin. Vollegrondsgroenteteelt / Praktijkonderzoek voor de Akkerbouw en de Vollegrondsgroenteteelt, 1998
Zenodo (CERN European Organization for Nuclear Research), Dec 31, 1982
We studied the host selection behaviour of Asobara tabida Nees in experiments in which this paras... more We studied the host selection behaviour of Asobara tabida Nees in experiments in which this parasitoid could choose between equal numbers of larvae of Drosophila melanogaster and larvae of one of the following 4 species: D. busckii, D. funebris, D. immigrans and D. subobscura. We found that: 1) the percentage parasitism in a host species increased with the survival probability of A. tabida in larvae of that species; 2) though the percentage parasitism was often the result of active rejection by the parasitoid of larvae of the less profitable species, the parasitoid often gave up before it had inserted its ovipositor in the host; this occurred: a) when a larva, after initial detection by the parasitoid, kept motionless and could not be located. b) when after detection of a larva the wasp failed to hit it with the ovipositor; the number of encounters in which the parasitoid gave up after missing stabs with the ovipositor was negatively correlated with the size of the host larvae c) when the wasp hit the larva but failed to pierce the host's skin with the ovipositor; the number of encounters in which the parasitoid gave up after it failed to pierce the host's skin was positively correlated with skin thickness d) after a combination of the events mentioned under b) and c) e) when the wasp was frightened off by vigorous wriggling of the host larva; 3) the host selection behaviour of A. tabida was affected by previous experience of the wasps with a host species; 4) A. tabida prefers D. subobscura over the 4 other species and attacks this species more efficiently than the other 4 species. D. subobscura is the only native species used in our study, D. busckii, D. funebris, D. immigrans and D. melanogaster are alien in western Europe, but may dominate the Drosophila fauna during the second part of the summer. Oviposition by A. tabida in larvae of alien Drosophila species with a low survival probability for the parasitoid's eggs may therefore only occur when native host species are scarce and may thus help the parasitoid to persist during the period when the preferred hosts cannot be found.
Drukwerk: Xerox/OBT Foto's: zie vermelding naast de foto´s www.rda.nl Raad voor Dierenaangelegenh... more Drukwerk: Xerox/OBT Foto's: zie vermelding naast de foto´s www.rda.nl Raad voor Dierenaangelegenheden Bezuidenhoutseweg 73 Naar de inhoudsopgave van het rapport 53% D ie r e n i n d e n a t u u r P r o e f d i e r e n 53% D ie r e n i n d e n a t u u r P r o e f d i e r e n 53% D ie r e n i n d e n a t u u r P r o e f d i e r e n Lees meer in hoofdstuk 1 Lees meer in hoofdstuk 2 Lees meer in hoofdstuk 3 Lees meer in hoofdstuk 7 Lees meer in hoofdstuk 10 Lees meer in hoofdstuk 9 Lees meer in hoofdstuk 8 Naar de inhoudsopgave van het rapport P r o d u c t i e d i e r e n R e c r e a t i e d i e r e n 80% 72% 63% 54% erser ieren artner Pets, passie en professionaliteit Gaat het goed met het welzijn van onze dierbare metgezellen of zijn we blind voor onze eigen tekortkomingen in onze omgang met dieren? Honden horen niet in bed. Lees meer in hoofdstuk 5 Zijn dierentuinen nog van deze tijd? Een dierentuin is geen pretpark. Lees meer in hoofdstuk 6 Dieren hebben een eigen waarde, omdat ze onderdeel zijn van het ecosysteem Er bestaat een grote middengroep die vertrouwen heeft hoe we in Nederland met dieren omgaan. We zien weinig tot geen verschil in achtergrond (stad/ platteland, leeftijd). Dieren hebben moreel recht op leven Mensen hebben morele plicht om goed te doen voor dieren Dieren hebben een eigen waarde, omdat ze gevoel hebben Wet-en regelgeving Lees meer in hoofdstuk 11 Lees meer in hoofdstuk 12 Lees meer in hoofdstuk 13 Naar een dierwaardige kringlooplandbouw Is het welzijn inclusief gezondheid van productiedieren verbeterd? Wat zijn nog hardnekkige welzijnsissues? Stel het welzijn van dieren centraal in de transitie naar een kringlooplandbouw. Lees meer in hoofdstuk 4 eer in uk 14
Lutra, 2009
Temporary bald spots in mammals are usually related to moult. Alternatively, they may be a sign o... more Temporary bald spots in mammals are usually related to moult. Alternatively, they may be a sign of bad health, or a side effect of hormones. Pond bats (Myotis dasycneme) commonly show partial baldness. Using data from more than 2,200 pond bats, captured between 2003 and 2008, we investigate the possible social, ecological and physiological factors involved in this phenomenon. A large proportion of pond bats were partly bald during a short period of the year, mainly between mid-May and the first week of August. Hair loss was observed in just a small area on the back of the bat, between the shoulder blades. These bald spots were much more common among females than males. The occurrence of baldness was temporally correlated with the nursing period of females. To test the generality of these patterns we studied animals from museum collections and photographs of roosting animals taken during the past two decades. While these data remain anecdotal, the position of the bald spots and the timing of appearance are consistent with those found in this study.
Zenodo (CERN European Organization for Nuclear Research), Aug 18, 1982
This paper presents the results of a study of superparasitism and host discrimination by Asobara ... more This paper presents the results of a study of superparasitism and host discrimination by Asobara tabida Nees. We found that: (1) A. tabida females are able to distinguish unparasitized hosts from those previously parasitized by themselves or by a conspecific; (2) There is no evidence that A. tabida females are able to distinguish hosts in which they laid an egg themselves from hosts parasitized by conspecifics; (3) A. tabida females, unlike those of Leptopilina heterotoma cannot discriminate between hosts with different numbers of eggs; (4) Superparasitism may occur because: (a) inexperienced females of A. tabida may initially lay two eggs during one oviposition. (b) a female A. tabida may re-attack a host after oviposition within the period needed for building up the factor which causes avoidance of superparasitism. (c) the restraint to oviposit in parasitized hosts breaks down when a female A. tabida only meets parasitized hosts and does not lay eggs during a period of at least 8 hours. (d) females that have never oviposited in unparasitized hosts do not refrain from oviposition in parasitized hosts. We discuss whether superparasitism by insect parasitoids can be adaptive under particular circumstances.
Netherlands Journal of Zoology, 1981
This paper presents the results of a study of superparasitism and host discrimination by Asobara ... more This paper presents the results of a study of superparasitism and host discrimination by Asobara tabida Nees. We found that: (1) A. tabida females are able to distinguish unparasitized hosts from those previously parasitized by themselves or by a conspecific; (2) There is no evidence that A. tabida females are able to distinguish hosts in which they laid an egg themselves from hosts parasitized by conspecifics; (3) A. tabida females, unlike those of Leptopilina heterotoma cannot discriminate between hosts with different numbers of eggs; (4) Superparasitism may occur because: (a) inexperienced females of A. tabida may initially lay two eggs during one oviposition. (b) a female A. tabida may re-attack a host after oviposition within the period needed for building up the factor which causes avoidance of superparasitism. (c) the restraint to oviposit in parasitized hosts breaks down when a female A. tabida only meets parasitized hosts and does not lay eggs during a period of at least 8 hours. (d) females that have never oviposited in unparasitized hosts do not refrain from oviposition in parasitized hosts. We discuss whether superparasitism by insect parasitoids can be adaptive under particular circumstances.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 2, 2014
Coexistence of species sharing the same resources is often possible if species are phylogenetical... more Coexistence of species sharing the same resources is often possible if species are phylogenetically divergent in resource acquisition and allocation traits, decreasing competition between species. Developmental and life history traits related to resource use are influenced by environmental conditions such as temperature, but thermal trait responses may differ among species. An increase in ambient temperature may, therefore, affect trait divergence within a community and potentially species coexistence. Parasitoids are interesting models to test this hypothesis, because multiple species commonly attack the same host, and employ divergent larval and adult host use strategies. In particular development mode (arrested or continued host growth following parasitism) has been recognized as a major organizer of parasitoid life histories. Here we used a comparative trait-based approach to determine thermal responses of development time, body mass, egg load, metabolic rate and energy use of the coexisting Drosophila parasitoids Asobara tabida, Leptopilina heterotoma, Trichopria drosophilae and Spalangia erythromera. We compared trait values between species and development modes, and calculated trait divergence in response to temperature, using functional diversity indices. Parasitoids differed in their thermal response for dry mass, metabolic rate and lipid use throughout adult life, but only teneral lipid reserves and egg load were affected by developmental mode. Species-specific trait responses to temperature were probably determined by their adaptations in resource use (e.g. lipogenesis or ectoparasitism). Overall, trait values of parasitoid species converged at the higher temperature. Our results suggest that local effects of warming could affect host resource partitioning by reducing trait diversity in communities.
The dynamics of parthenogenesis-inducing Wolbachia bacteria
The role of host-plant odours in the attraction of Leptomastix dactylopii and Leptomastidea abnormis, parasitoids of the citrus mealybug, Planococcus citri
FORAGING STRATEGIES IN INDIVIDUALLY SEARCHING ANTS, CATAGLYPHIS BICOLOR (HYMENOPTERA: FORMICIDAE) by R. WEHNER, R. D. HARKNESS & P. SCHMID-HEMPEL, 1983. Gustav Fischer Verlag Stuttgart-New York. 79 pp. DM 34
Netherlands Journal of Zoology, 1983
... YEAR: 1983. PUB TYPE: Book (ISBN 0895741857 [pbk]). VOLUME/EDITION: Volume 1. PAGES (INTRO/BO... more ... YEAR: 1983. PUB TYPE: Book (ISBN 0895741857 [pbk]). VOLUME/EDITION: Volume 1. PAGES (INTRO/BODY): SUBJECT(S): Ants; Behavior; Food; Tunisia; Greece. DISCIPLINE: No discipline assigned. LC NUMBER: QL568.F7 W43 1983. HTTP: LANGUAGE: English. ...
Biological control of citrus-mealybug in a commercial crop of ornamental plants in the Netherlands
Does a deletion in a virus-like particle protein pleiotropic have effects on the reproductive biology of a parasitoid wasp?
HAL (Le Centre pour la Communication Scientifique Directe), 2003
Oecologia, Oct 30, 2013
Coexistence of species sharing the same resources is often possible if species are phylogenetical... more Coexistence of species sharing the same resources is often possible if species are phylogenetically divergent in resource acquisition and allocation traits, decreasing competition between species. Developmental and life history traits related to resource use are influenced by environmental conditions such as temperature, but thermal trait responses may differ among species. An increase in ambient temperature may, therefore, affect trait divergence within a community and potentially species coexistence. Parasitoids are interesting models to test this hypothesis, because multiple species commonly attack the same host, and employ divergent larval and adult host use strategies. In particular development mode (arrested or continued host growth following parasitism) has been recognized as a major organizer of parasitoid life histories. Here we used a comparative trait-based approach to determine thermal responses of development time, body mass, egg load, metabolic rate and energy use of the coexisting Drosophila parasitoids Asobara tabida, Leptopilina heterotoma, Trichopria drosophilae and Spalangia erythromera. We compared trait values between species and development modes, and calculated trait divergence in response to temperature, using functional diversity indices. Parasitoids differed in their thermal response for dry mass, metabolic rate and lipid use throughout adult life, but only teneral lipid reserves and egg load were affected by developmental mode. Species-specific trait responses to temperature were probably determined by their adaptations in resource use (e.g. lipogenesis or ectoparasitism). Overall, trait values of parasitoid species converged at the higher temperature. Our results suggest that local effects of warming could affect host resource partitioning by reducing trait diversity in communities.
In parasitoid wasps, self-superparasitism (oviposition into a host already parasitized by the fem... more In parasitoid wasps, self-superparasitism (oviposition into a host already parasitized by the female herself) often contributes less to the reproductive success of the parasitoid than oviposition into a host previously parasitized by a conspecific (conspecific superparasitism). It could therefore often be profitable for parasitoids to avoid self-superparasitism. This requires a mechanism for either (1) the avoidance of previously searched areas and/or (2) the rejection of hosts containing eggs laid by the searching female. We investigated whether the solitary parasitoid Epidinocarsis lopezi is able to avoid self-superparasitism. We show that visits to previously searched patches were shorter than visits to unsearched patches and conclude that E. lopezi females leave a trail odour on patches they have searched. No differences were found between the time on patches previously searched by the wasp itself and on patches visited by conspecifics. However, E. lopezi superparasitizes fewer hosts previously parasitized by itself than hosts parasitized by a conspecific. Thus, they recognize an individual-specific mark in or on the host. We discuss how patch marking and host marking enable E. lopezi to avoid self-superparasitism.
Heat resistance of parasitoids and their hosts
HAL (Le Centre pour la Communication Scientifique Directe), Aug 20, 2007
Poste
Entomologische Berichten, 1992
The eucoilid wasp Leptopilina longipes had never been found in The Netherlands and its biology wa... more The eucoilid wasp Leptopilina longipes had never been found in The Netherlands and its biology was unknown. L. longipes is related to other northern European eucoilid species with parasitize drosophilid flies developing in decaying fruit, plant material and fungi. We put baits of decaying cucumber and mushroom out in woodlands in The Netherlands. An adult L. longipes was found on a cucumber bait in the field, and more were reared from a cucumber bait collected at the same site. We show that L. longipes is a parasitoid of the larvae of Scaptomyza pallida and Drosophila species of the quinaria group, as predicted on the basis of its phylogenetic relationships with other eucoilid species.
In contrast to earlier claims we show in this paper that insect parasitoids are able to recognize... more In contrast to earlier claims we show in this paper that insect parasitoids are able to recognize parasitized hosts before they have oviposited in unparasitized hosts, and hence, that host discriminatio'h needs not be learnt. We show this by presenting experiments with two strains of Leptopihna heterotoma and with T r i c h o p m m a evanescens, and by reanalysis of the data sets on Which the learning hypothesis was based. We discuss the functional reasons for superparasitism by both inexperienced and experienced parasitoids and suggest how to proceed with research on the causation of superparasitism.
Patch marking and recognition of an individual-specific mark in parasitized hosts by the solitary parasitoid Epidinocarsis lopezi
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Papers by Jacques Van Alphen