To understand the factors governing the diversity, abundance and host associations of parasitoids attacking frugivorous drosophilid flies on Iriomote-jima, a subtropical island of Japan, we monitored parasitism on several occasions over the period 2003–2009. Fifteen drosophilid and 12 parasitoid species were recorded. Three species of Drosophila, D. bipectinata, D. albomicans and D. takahashii, bred abundantly in banana baits, though their abundance varied between years and seasons. Frequent parasitoid species were Asobara japonica, A. pleuralis (Braconidae), Leptopilina ryukyuensis and L. pacifica (Figitidae). L. victoriae was recorded only in December 2003. In addition, host acceptance and host suitability of the four most frequently recorded parasitoid species were studied in the laboratory. Most parasitoid and drosophilid species showed species-specific associations with more than one antagonist species, suggesting that they have been subjected to complex coevolutionary interactions. In addition, host range of most of the parasitoid species included one of the three major Drosophila species, suggesting that the abundance of potential hosts is one of the factors determining the evolution of parasitoid host use., Biljan Novkovic ... [et al.]., and Obsahuje seznam literatury
Dinocampus coccinellae females which eclose in mid-summer have the opportunity to oviposit in overwintered or in newly eclosed coccinellid hosts. Given the short further longevity of overwintered hosts, offspring fitness would be increased by ovipositing preferentially in young hosts. Laboratory choice tests show that female D. coccinellae do exhibit such a preference.
Dinocampus coccinellae is a parasitoid wasp usually parasitizing ladybird beetles of the tribe Coccinellini. A field survey conducted between March and November 2016 revealed three hosts of this parasitoid in the Srinagar district of the Indian state of Jammu and Kashmir: two members of the Coccinellini (Oenopia conglobata and Coccinella undecimpunctata) and one of the Chilocorini (Priscibrumus uropygialis). Proportion of the latter (atypical) host that were parasitized was 0.09 and intermediate between that recorded for C. undecimpunctata (0.06) and O. conglobata (0.14). A series of laboratory experiments revealed that while a member of Coccinellini (O. conglobata) was more often attacked by D. coccinellae than a member of Chilocorini (P. uropygialis), the proportions of each species from which parasitoids emerged did not differ significantly. There were no significant differences between D. coccinellae females bred from O. conglobata and P. uropygialis, with respect to selection of the two host species and their suitability for the development of the parasitoid. However, members of the Chilocorini other than P. uropygialis (Chilocorus infernalis and Simmondsius pakistanensis) were rarely attacked by D. coccinellae and parasitoid larvae did not emerge from any of those attacked. The results of our experiments indicate that in Kashmir Himalayas D. coccinellae is adapted to parasitize hosts belonging to both Coccinellini and Chilocorini., Amir Maqbool, Imtiaz Ahmed, Piotr Kiełtyk, Piotr Ceryngier., and Obsahuje bibliografii
Diachasmimorpha longicaudata is the most widely used endoparasitoid in biocontrol programmes against various species of tephritids and is continuously mass-reared under laboratory conditions at a constant temperature; however, little is known about how varying the temperature might affect the effectiveness of the mass rearing of immature D. longicaudata. This study aimed to determine the optimum temperature for the development of larvae D. longicaudata the larvae of its host, Bactrocera dorsalis. Third-instar B. dorsalis were exposed for 4 h to five pairs of parasitoids, and then they were kept at one of six temperatures ranging from 19°C to 34°C. The activities of three major antioxidant enzymes (CAT, POX, SOD) were individually measured 4, 24, 48 and 72 h after exposure to each of the six temperatures. The results were as follows: for CAT the highest CAT activities were recorded at 25°C (intervals 5-24 h and 25-48 h), at 28°C (interval 0-4 h) and at 31°C (interval 49-72 h), and for POX and SOD identically at 25°C (intervals 0-4 h, 5-24 h) and at 31°C (intervals 25-48 h, 49-72 h), respectively. Subsequently, the effects keeping the parasitized larvae at these different temperatures on the biological attributes of D. longicaudata reared under laboratory conditions were investigated. The percentage of their eggs that hatched, percentage of adults that emerged, pupal weight and longevity were significantly greater than that recorded for the control when the parasitized host larvae were kept at 28°C for 4 h, 25°C for 5 and 48 h and 31°C for 49 and 72 h.
We investigated the effect of the feeding behaviour of young larvae of Pieris rapae crucivora Boisduval (Pieridae) on parasitism by the parasitoid wasp, Cotesia glomerata (L.) (Braconidae). Young, 1st-3rd instar larvae used approximately three sites for feeding each day. When not feeding, they moved a short distance away from the feeding sites (= feeding marks) and rested. For first, second and third instar larvae, the distances from the new mark, made within 24 h, to larva at rest were, respectively, about 3.5 mm, 5 mm and more than 10 mm. To resume feeding, they moved back to one of the former feeding sites or a new site. The percentage of the feeding marks older than 24 h that attracted parasitoids was less than 50%. Time spent searching for hosts by a parasitoid was short. Larvae placed 5 mm or more from a feeding mark were less parasitized than the larvae placed near a mark. The number of feeding marks affected parasitism. When comparing single-marked and triple-marked leaves, the percentage parasitism of the larvae on the latter was significantly lower than that of the larvae on the former. On triple-marked leaves, parasitoids visited each mark unevenly. Accordingly, the time spent searching each mark differed significantly among the marks. Because of this confusing effect, hosts are considered to be reducing the risk of parasitism. Our results demonstrate that the feeding habits of young larvae of P. rapae crucivora are adaptive in terms of reducing the risk of parasitism by C. glomerata., Aya Nakayama, Keiji Nakamura, Jun Tagawa., and Obsahuje bibliografii
The function and structure of the ovipositor in Hymenoptera have been studied intensively, although there is a lack of information on the external sheaths. We provide here a contribution on the structure of the external sheaths of the ovipositor of the parasitic wasp Aphidius ervi, in particular the secretory structure is described for the first time. These glands are made up of a large epithelial structure that consists a single layer of large secretory cells that occupy most of the lumen of the valve and belong to gland cell class 1. Based on the different features of the glands, a lubricating and/or host marking function is hypothesized and discussed., Sara Ruschioni, Paola Riolo, Roberto Romani, Donatella Battaglia, Nunzio Isidoro., and Obsahuje bibliografii
Monoctonus paulensis is a solitary parasitoid of several species of aphids, including the pea aphid, Acyrthosiphon pisum. We evaluated host-instar selection by comparing the parasitoid's preference for the four nymphal instars of the pea aphid, presented two at a time in dichotomous choice tests. Females parasitized more, and laid more eggs in, the relatively smaller aphids among those available. This preference was independent of aphid instar: L1 > L2 > L3 > L4. Preference was not influenced by female size or age. Normal and anaesthetized aphids were accepted equally. The total time needed by a female to capture, position, and parasitize an aphid varied among host instars, with fourth instars requiring nearly twice as much time as first, second, and third instars. The probability of an attacked aphid escaping or avoiding parasitism increased with aphid instar, from ~10% in first and second instars to ~50% in fourth instars. Although fourth-instar pea aphids contain more resources for offspring development than smaller counterparts, it may not be profitable for a female to invest opportunity time in attacks on large aphids.
Life table data of natural enemies are often used to understand their population dynamics and estimate their potential role in the biological control of pests. Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae) is an important pest of several crops and its intrinsic rate of population increase (rm) is 0.282 at 22°C. The life table parameters (immature mortality, developmental time, sex ratio of emerging adults, fecundity and longevity) of Praon volucre (Haliday) (Hymenoptera: Braconidae: Aphidiinae) parasitizing M. euphorbiae were estimated in a climatic chamber at 22 ± 1°C, RH 70 ± 10% and 12 h photophase. Immature mortality was 8.2%, developmental time of males and females was 13.9 and 14.4 days, respectively, and the sex ratio was 0.55 (= fraction of females). Parasitoid fecundity was 504 eggs and longevity 11 days. The net rate of reproduction (R0) was 207.5 females and the intrinsic rate of population increase (rm) 0.281 females/female/day. The time for doubling the population (TD) was 2.45 weeks. P. volucre has a population growth rate similar to that of its host M. euphorbiae and might therefore be a good candidate for the biological control of this aphid. and Juracy Caldeira Lins jr., Vanda Helena Paes Bueno, Diego Bastos Silva, Marcus Vinicius Sampaio, Joop C. van Lenteren.
Leafrollers can experience high levels of indigenous parasitism in organically managed apple orchards and the augmentative release of specific parasitoid species to suppress these secondary pests may be advantageous in orchards converting to non-chemical pest management. Caged and uncaged releases of two ichneumonid [Apophua simplicipes (Cresson) and Glypta variegata Dasch] and two braconid (Macrocentrus linearis Nees and Apanteles polychrosidis Viereck) koinobiont endoparasitoids of the obliquebanded leafroller, Choristoneura rosaceana (Lepidoptera: Tortricidae) on host-infested potted apple trees were conducted to assess the parasitoids' abilities to find and successfully parasitize sentinel hosts under orchard conditions. Seasonal timing of the trials varied for each parasitoid species, based on their relative performance under simulated summer/fall conditions in laboratory trials. After the release of five or fifty parasitoid females, the mean percent parasitism of leafroller larvae collected from infested trees ranged from 0 to 75% depending on the parasitoid species involved. Although caged releases tended to increase the percentage of live parasitized hosts in release treatments, uncaged releases provided a more realistic assessment of the parasitoid's ability to seek and find hosts within an infested area over a longer period. Release of the large, solitary A. simplicipes, had the most significant impact on the host population density.
A suitable host provides, at least, the minimum nutritional and physiological conditions for the development of the immature stages of a parasitoid. Host quality may influence the developmental time, mortality rate, longevity and fecundity of parasitoids. This work evaluates the suitability and quality of Aphis gossypii Glover, Brevicoryne brassicae (Linné), Myzus persicae (Sulzer), Rhopalosiphum maidis (Fitch) and Schizaphis graminum (Rondani) as hosts for Aphidius colemani Viereck. Twenty second-instar nymphs of each aphid species were exposed to parasitism for one hour, and then kept in a climatic chamber at 22 ± 1°C, 70 ± 10% RH and a 12 h photophase. The aphid B. brassicae was unsuitable for the development of A. colemani. The different aphid host species varied in size: M. persicae > (R. maidis = S. graminum) > A. gossypii. Parasitoid fitness decreased accordingly when reared on (M. persicae = R. maidis) > S. graminum > A. gossypii. Large hosts seem to be better than small hosts based on parasitoid size. Egg load of A. colemani was related probably more on the ability of the parasitoid larva to obtain nutritional resources from the different host species than on host size.