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The solitary parasitoids Aphidius erviHaliday (Hymenoptera: Aphidiidae) and Aphelinus asychisWalker (Hymenoptera: Aphelinidae) attacked but generally did not oviposit in pea aphids parasitized by the other species. Wasps selectively oviposited in unparasitized hosts when given a choice. Host discrimination depended on the recognition of internal cues. Females of A. asychiseither could not recognize or ignored A. ervi'sexternal host marking pheromone. Under most conditions, A. ervisurvived in superparasitized hosts, killing competing A. asychislarvae by physical attack and possibly physiological suppression. The outcome of larval competition was not affected by oviposition sequence or age difference between larvae; A. asychissurvived only when it had substantially completed larval development before the host was superparasitized by A. ervi.It is suggested that competition for host resources incurs a cost, for the winner in terms of reduced size or increased development time and for the loser in terms of lost progeny and searching time. Consequently, heterospecific host discrimination can be functional. Internal, and probably general, cues enable wasps to recognize and avoid oviposition in hosts already parasitized by an unrelated species.  相似文献   

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Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae) is an ectoparasitoid of several stored-product insect pests. Very little information has been published on its biology and development in host larvae, which typically are concealed within seeds. We documented the development of P. cerealellae within fourth instar larvae of its concealed host, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) infesting cowpea seeds. The preimaginal life stages of the parasitoid were characterized for the first time using morphological structures revealed by microscopic techniques including scanning electron microscopy. Pteromalus cerealellae produces hymenopteriform eggs and larvae. Eggs hatch into 13-segmented first instar larvae with peripneustic condition of spiracles. The larvae have simple, tusk-like mandibles, whereas the mandibles of the pupae and the adults are of the conventional toothed types. Using statistical analyses of the sizes of the larval mandibles and head capsules in conjunction with reliable characters such as the number of exuviae on the body of parasitoid larvae, cuticular folding, and excretion of the meconium, we recorded four larval instars for P. cerealellae. The data showed significant positive correlations between larval mandible lengths and widths of larval head capsules, as well as between mandible lengths and larval instars, suggesting that mandible length is a good predictor of the number of instars in P. cerealellae. Developmental time from egg to adult emergence was ∼12 d for females and ∼11 days for males at 30 ± 1°C, 70 ± 5% r.h. and 12L:12D photoperiod.  相似文献   

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The presence of two species of Phthiraptera, Bovicola caprae (Gurlt, 1843) (Ischnocera: Bovicoliidae) and Solenopotes binipilosus (Fahrenholz, 1916) (Anoplura: Linognathidae), is reported for the first time from Pudu puda (Molina, 1782).  相似文献   

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The bionomics and conservation status of a threatened, endemic fish Puntius denisonii has been reported.  相似文献   

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Juan C. Paggi 《Hydrobiologia》1996,319(2):137-147
Daphnia (Ctenodaphnia) menucoensis n. sp. is described from various localities in arid and semiarid Argentina. D. menucoensis has no ocellus, and a characteristic head, fornices, ephippium and denticular arrangement of postabdomen in females and males. The species belongs to a group, along with D. mediterranea, D. dolichocephala Negrea 1984, and D. salina, sharing ecological and morphological characteristics.  相似文献   

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Paranosema (Nosema) locustae Canning has persisted in grasshopper populations in the Inner Mongolia Rangeland since spore treatment was applied in 1993. In the treatment year, a 58.32–71.43% reduction of grasshoppers was recorded and 59.26–80.36% of surviving grasshoppers of various species were infected. In the years following application, prevalence of P. locustae varied from 13.65% to 60.71%, demonstrating that P. locustae remains in grasshopper populations for many years. Infection prevalence was more than 60.00% for Dasyhippus barbipes (F.-W.), Bryodema luctuosum luctuosoma (Stoll) and Angaracris barabensis (Pall.) in 1993 but was very variable, ranging from 20.00% to 60.71% over the subsequent nine years. Disease prevalence was 43.72–60.71% in 1993 and 1994 for Oedaleus asiaticus B.-Bienko and Myrmeleotettix palpalis (Zub.) but gradually declined to approximately 20%, where it remained. Persistence of P. locustae in grasshopper populations may be important in keeping densities below economic thresholds for a number of years after application. Handling Editor: Helen Roy.  相似文献   

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A new species of chewing louse, Myrsidea agarwali, is described from Garrulax lineatus lineatus (Passeriformes: Timaliidae) from the Rampur district (India). A key is provided for the identification of males and females of Myrsidea from birds of the genus Garrulax.  相似文献   

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In the southeastern United States, South American Scapteriscus mole crickets are serious pests of turf and pasture grasses and vegetable seedlings. The larval stage of Pheropsophus aequinoctialis L. is a specialist predator of Scapteriscus mole cricket eggs and is currently under evaluation as a potential biological control agent. The objective of this study was to understand the oviposition behavior of P. aequinoctialis. The results indicated that in two-choice substrate oviposition arenas, female P. aequinoctialis significantly preferred to lay eggs in sand with mole cricket tunnels compared with artificially created tunnels or sand without tunnels. Physical tunnel presence influenced oviposition depth, but was not the only factor influencing oviposition. The reproductive strategy and behavior of P. aequinoctialis is discussed in relation to its specialized life history and to other carabid beetles displaying close host associations.  相似文献   

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A survey for natural entomopathogenic fungi of the Chagas disease vector Triatoma infestans was conducted in five provinces of Argentina since 2001. Nymphs (1.5%) and adults (3.3%) infected with a strain of the fungus Beauveria bassiana were found at Dean Funes, Córdoba province, Argentina. Field collected insects that died in the laboratory were maintained in moist chambers and incubated at 22 °C. Beauveria bassiana from infected insects was cultured on SDAY media. Pathogenicity tests were conducted with a conidial suspension (1 × 107 conidia/ml) of this isolate on T. infestans adults. A mortality rate of 100% was obtained at 15 days post-infection. This is the first record of natural infection of T. infestans by B. bassiana.  相似文献   

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In the savanna-like Brazilian biome caatinga, the arboreal and polydomous ant Crematogaster brevispinosa rochai can be found cohabiting with two closely related Nasutitermes species (N. corniger and N. ephratae). This ant occupies variably sized portions of the termite nests and maintains a physical separation with its hosts by plugging the cells of the boundary areas with fibrous material. Although all the analysed cohabiting C. b. rochai nests were queenless, they always contained brood, especially from male and female reproductive castes. Interaction experiments between workers of C. b. rochai and workers or soldiers of N. ephratae revealed a low level of aggressiveness between the two species that contrasts with the aggressiveness of both C. b. rochai and N. ephratae in encounters with other ant (Azteca cf. chartifex, Cephalotes pusillus) or termite (M. cf. indistinctus) species. The association could benefit both ants (additional nesting sites, brood rearing places) and termites (protection against predators, dead ants or ant refuses as source of nitrogen).  相似文献   

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Siderocelis irregularis Hindák, representing a genus Siderocelis (Naumann) Fott that is known from European temperate waters, was identified as a common phytoplankter in Lake Tanganyika. It was found aposymbiotic as well as ingested (possibly endosymbiotic) in lake heterotrophs, mainly Strombidium sp. and Vorticella spp. The morphology and ultrastructure of the species, studied with LM, SEM and TEM, are described with emphasis on the structure of the cell wall and the pyrenoid. Presented at the International Symposium Biology and Taxonomy of Green Algae V, Smolenice, June 26–29, 2007, Slovakia.  相似文献   

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Conservation status, identification, distribution, abundance, habitat and ecology, threats, conservation actions and recommendations of a endemic bagrid catfish, Dianchi bullhead, Pseudobagrus medianalis were introduced based on data and knowledge from a GEF project in Lake Dianchi, Yunnan, China.  相似文献   

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Trematolobelia (Campanulaceae: Lobeliodeae) is a genus of semelparous pliestesial pachycaul rosette treelets endemic to the Hawaiian Islands. Eight species are re-cognized. The most widespread is T. macrostachys, found in the Ko‘olau Mountains of O‘ahu and on Moloka‘i and Maui. The remainder are single-island endemics: T. auriculata (Lna‘i); T. grandiflora (Hawai‘i); T. kaalae, comb. et stat. nov. (Wai‘anae Mountains of O‘ahu); T. kauaiensis (Kaua‘i); T. rockii (Moloka‘i); T. singularis (Ko‘olau Mountains of O‘ahu); and T. wimmeri (Hawai‘i).  相似文献   

19.
Mitat Aydogdu 《Biologia》2008,63(2):245-248
A new species of the genus Chelonus Panzer, 1806, C. beyarslani sp. n., is described and illustrated from Western Anatolia (Turkey). It is morphologically similar to Chelonus oculator (F., 1775), from which it differs mainly in the characteristics of antennomeres, first flagellomere, propodeum, propodeal tubercle and mesosoma.  相似文献   

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The poorly known scorpionfish, Scorpaena taeniophrys, originally described from two specimens from the Philippines, is redescribed as a valid species of Sebastapistes. Sebastapistes taeniophrys differs from all other congeners in having a combination of 15 pectoral-fin rays, 31–33 scale rows in longitudinal series, 11–14 pored lateral-line scales, 3 predorsal scale rows, 12 gill rakers, 3 suborbital spines, absence of coronal spines, lower opercular spine with a median ridge and not covered with scales, ctenoid body scales, several dark transverse bands on ventral surface of mandible, a distinct elongate black blotch distally between the second or third and seventh dorsal-fin spines, and no black blotch on the nape.  相似文献   

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