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Egg Parasitoid (egg + parasitoid)
Selected AbstractsEgg parasitoids of Australian Coreidae (Hemiptera)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2001Ian D Naumann Abstract Ten microhymenopteran species are recorded as parasitoids of the eggs of coreid bugs in Australia: Chrysochalcissa olivacea Girault (Torymidae) from Amorbus biguttatus Stål and Pternistria bispina Stål; two species of Anastatus Motschulsky (Eupelmidae) from Mictis profana (F.), Amorbus alternatus Dallas, Amblypelta lutescens lutescens (Distant) and an unidentified coreid; Xenoencyrtus hemipterus (Girault) (Encyrtidae) from Amorbus obscuricornis (Westwood) and Gelonus tasmanicus (Le Guillou); Ooencyrtus caurus Huang and Noyes (Encyrtidae) from A. lutescens lutescens;Centrodora darwini (Girault) (Aphelinidae) from an unidentified coreid; and four species of Gryon Haliday (Scelionidae) from Aulacosternum nigrorubrum (Dallas), A. lutescens lutescens, Amorbus rubicundus Stål, Mictis caja Stål, M. profana and an unidentified coreid. Alternate hosts and biological control prospects are discussed. [source] Maternal size and age affect offspring sex ratio in the solitary egg parasitoid Anaphes nitensENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2007Serena Santolamazza-Carbone Abstract In this study, the effects of maternal age, diet, and size on offspring sex ratio were investigated for the solitary egg parasitoid, Anaphes nitens Girault (Hymenoptera: Mymaridae), both outdoors, during the winter, and inside a climatic chamber under favourable constant conditions. During the winter of 2005,2006, each of seven groups containing 40 1-day-old females was mated and randomly distributed among two treatments: (treatment 1) a droplet of undiluted honey ad libitum + one fresh egg capsule of the snout beetle Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae) as host; (treatment 2) drops of water + one fresh egg capsule of G. scutellatus. We recorded the lifetime fecundity, the daily sex allocation, and the lifetime offspring sex ratio to study the existence of a relationship with maternal characteristics. Moreover, we assessed the effect of location (outdoors vs. indoors) and group (groups are representative of early, mid, and late winter) on sex ratio. The most important factor that biased the sex ratio was maternal body size: larger females of both treatments produced more female offspring. As females of A. nitens could gain more advantage than males from body size, larger mothers have a higher fitness return if they produce more daughters. The effect of the treatment was significant: starved females produced more females. Location and group were not significant. Fecundity and sex ratio were age dependent. Old mothers that received honey (treatment 1) had fewer offspring and a more male-biased offspring sex ratio, probably due to reproductive senescence and sperm depletion. Starved females (treatment 2) experienced reproductive decline earlier, perhaps because they invested more energy in maintenance rather than in reproduction. [source] Searching and oviposition behavior of a mymarid egg parasitoid, Anagrus nigriventris, on five host plant species of its leafhopper host, Circulifer tenellusENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000A.K. Al-Wahaibi Abstract Searching and oviposition behavior and parasitization ability of Anagrus nigriventris Girault (Hymenoptera: Mymaridae), an egg parasitoid of beet leafhopper, Circulifer tenellus (Baker) (Homoptera: Cicadellidae), were examined on five host plant species of beet leafhopper: sugar beet (Beta vulgaris L.), red stem filaree (Erodium cicutarium[L.]), peppergrass (Lepidium nitidum Nuttall), desert plantain (Plantago ovata Forsskal), and London rocket (Sisymbrium irio L.). Beet leafhopper embeds its eggs in the tissues of these plant species. For each plant species, A. nigriventris behavior was examined on plants with and without beet leafhopper eggs. Experimental design was a 5 (plant species) by 2 (host eggs present/absent) factorial. Additionally within each treatment, parasitoid behavior was observed over a 22-h period at five different observation periods: t=0, 3, 6, 9, and 22 h where t=0 h represents initial exposure of the insect with the plant. The behavioral events observed were: ,fast walking' (general searching), ,slow walking' (intensive searching), ovipositor probing, grooming, feeding, and resting. Significant differences (,=0.05) among plant species in time spent on the plant, percentage of host eggs parasitized, and behavioral variables associated with intensive searching and oviposition all indicated that the plant species fell into two groups: ,preferred' plants (sugar beet, London rocket, and peppergrass), and ,unpreferred' plants (filaree and plantago). These variables also indicated that the parasitoids spent more time on, searched more, probed more, and oviposited more in plants with host eggs than plants without host eggs. Consistent effects of time (over the observation periods from t=0 to t=22 h) generally were detected only in the preferred plant species that had host eggs present. In these cases, intensive searching and probing decreased as time advanced, while variables related to general searching (,fast walking') and abandoning host egg patches (leaving the plant) tended to increase over time. [source] Biology of Anagrus atomus (Hymenoptera: Mymaridae), an egg parasitoid of the grape leafhopper Arboridia kermanshah (Homoptera: Cicadellidae)ENTOMOLOGICAL SCIENCE, Issue 3 2004Shahram HESAMI Abstract Biology, morphology and oviposition behavior of Anagrus atomus (Linnaeus), an egg parasitoid of the grape leafhopper Arboridia kermanshah Dlabola in Isfahan, Iran, were investigated. Adults were smaller than those so far reported from other regions. Females continuously drummed on plant surfaces with their antennae to search for host eggs. Parasitoid eggs hatched 2,3 days after oviposition, and A. atomus had two larval instars. First instar larvae were sacciform and immobile. Second instar larvae appeared 4 days after oviposition and were very active, and doubled their body length. The prepupal and pupal stages lasted for 1 and 5,6 days, respectively. Adult emergence began 16 days after oviposition, and peaked on day 17. [source] Winter survival and oviposition before and after overwintering of a parasitoid wasp, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae)ENTOMOLOGICAL SCIENCE, Issue 2 2004Takeshi TERAOKA Abstract Winter survival and oviposition before and after overwintering in Ooencyrtus nezarae, an egg parasitoid of phytophagous heteropterans, were examined in Osaka, Japan. Eggs of Riptortus clavatus parasitized by O. nezarae were kept under natural photoperiod and temperature. When honey was supplied, some female adults emerging from early September to late November overwintered. The percentage of overwintering individuals increased as the date of adult emergence advanced. Most female adults supplied with honey and hosts oviposited soon after emergence, then stopped laying eggs. Female adults emerging in mid-October and early November laid eggs and then overwintered. The induction of diapause in the field seems to vary greatly depending on host availability. Without honey, the survival time of female adults was very short, whether host eggs were supplied or not. After overwintering, most females began to lay eggs in early May if host eggs were supplied, and they produced both male and female progeny. In the study area, a legume field in Osaka, parasitization by O. nezarae was observed from early July to November. [source] The role of larval aggression and mobility in the transition between solitary and gregarious development in parasitoid waspsECOLOGY LETTERS, Issue 6 2000G. Boivin Models explaining the appearance of gregariousness in insect parasitoids assume the presence of a tolerance gene that enables nonsiblicidal behaviour in gregarious larvae. Under this assumption, nontolerant individuals should attack and kill tolerant individuals when sharing a host, making this behaviour susceptible to invasion by nontolerant individuals. We propose an alternative hypothesis where gregarious larvae retain their aggressiveness but are less mobile. We tested this hypothesis with two sympatric and congeneric species of Mymaridae, Anaphes victus and Anaphes listronoti, respectively, solitary and gregarious egg parasitoids of a Curculionidae, Listronotus oregonensis. Results obtained in competition experiments and from direct observation of movement in mymariform larvae of both species support the reduced mobility hypothesis. By being immobile while retaining their fighting capacity, A. listronoti mymariform larvae appear to optimize host utilization through gregarious development, but can still defend themselves against sympatric aggressive species. [source] Naturally occurring egg parasitoids of the genus Trichogramma (Hymenoptera: Trichogrammatidae) in a pomegranate orchard in TunisiaENTOMOLOGICAL SCIENCE, Issue 1 2010Ines KSENTINI Abstract Four Trichogramma species were found in a pomegranate orchard in Gabès, an arid region of Tunisia, from parasitized eggs of Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae), an economically important insect pest. Identification based on assessment of male genitalia and internal transcribed spacer 2 (ITS2) sequences showed that they were T. bourarachae Pintureau and Babault, 1988, T. oleae Voegelé and Pointel, 1979, T. cacoeciae Marchal, 1927 and T. evanescens Westwood, 1833. Trichogramma evanescens is reported for the first time in Tunisia. Trichogramma cacoeciae was the largely dominant species in the analyzed samples, whereas T. bourarachae was present in a minor portion of 1.38%. The implications of these results for attempts at controlling E. ceratoniae are discussed. [source] Assessing the Semelparity Hypothesis: Egg-guarding and Fecundity in the Malaysian Treehopper Pyrgauchenia tristaniopsisETHOLOGY, Issue 10 2002Ulrich E. Stegmann According to the semelparity hypothesis, iteroparous insects should provide either no maternal care or less care than related semelparous species. We present field data on reproductive output and maternal care in the Southeast Asian treehopper Pyrgauchenia tristaniopsis (Mt. Kinabalu, Borneo) relevant to a preliminary assessment of the hypothesis. In a mark-recapture experiment, more females than expected under semelparity were found to have oviposited a second clutch (37%). Female longevity was a of 75 d. Both these estimates were highly conservative. Oviposition was successive resulting in a of 46 eggs per clutch. Females provided care for eggs only, occasionally scraping their legs along the sides of the clutch apparently attempting to deter Brachygrammatella sp. egg parasitoids (Trichogrammatidae). Females straddled their clutch for a of 27 d, i.e. until 8 d after the beginning of first instar hatching. First instars hatched successively over a period of 11 d. When a female deserted her clutch, it contained about 37% yet unhatched eggs. Egg-guarding effectively reduced egg mortality: the earlier a female was experimentally removed from her clutch the higher the egg mortality. Displacement experiments demonstrated that egg-guarding is a behaviour actively maintained despite disturbances and specifically directed towards the egg clutch but not to the feeding site. We interpret our findings as being in accordance with the weaker claim of the semelparity hypothesis, i.e. the iteroparous P. tristaniopsis provided less maternal care than semelparous membracid species. Continued female feeding is discussed as a mechanism to display some level of care despite iteroparity. [source] Potential for controlling codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) in Argentina using the sterile insect technique and egg parasitoidsJOURNAL OF APPLIED ENTOMOLOGY, Issue 3 2010E. Botto Abstract Codling moth is the main pest affecting apples and pears worldwide. Most pest control strategies used against this insect have relied on the use of broad-spectrum insecticides which have led to non-desirable effects like pesticide resistance, residues in the environment, human health concerns and the reduction of access to international markets. Therefore, alternative pest control strategies that would result in sustainable fruit production systems while taking care of the environment are strongly promoted. The use of the sterile insect technique has proven to be a valuable pest control tactic within area-wide integrated pest management strategies, and its synergistic effect for Lepidoptera pests when combined with other biological control tactics such as parasitoids has been documented. The purposes of this research were to evaluate the response of an Argentinean codling moth strain to a sub-sterilizing radiation dose of 100 Gy and to assess the acceptability and suitability of sterile codling moth eggs by the egg parasitoids, Trichogramma cacoeciae (Marchal) and Trichogramma nerudai (Pintureau and Gerding). Irradiated female moths survived better than irradiated male moths and non-irradiated male and female moths. Also, the fecundity of irradiated female moths was reduced by more than 30% as compared to non-irradiated ones whereas their fertility was close to zero. The F1 generation was male biased with a lower fertility (inherited sterility) than the parental generation. Trichogramma cacoeciae and T. nerudai parasitized both fertile and sterile eggs. However, there was a significant reduction in acceptability for sterile eggs. Trichogramma nerudai parasitized more eggs than T. cacoeciae, but egg acceptability for this species was proportionally lower than for T. cacoeciae especially on eggs oviposited by irradiated females. Development to adult of both parasitoids species was not substantially affected by the origin of the eggs and the wasps had acceptable levels of adult emergence, survival and fecundity. These results provided useful information on the potential for controlling the codling moth using egg parasitoids and the sterile insect technique in Argentina. [source] Kairomonal effect of some saturated hydrocarbons on the egg parasitoids, Trichogramma brasiliensis (Ashmead) and Trichogramma exiguum, Pinto, Platner and Oatman (Hym., Trichogrammatidae)JOURNAL OF APPLIED ENTOMOLOGY, Issue 7-8 2002A. V. N. Paul These were followed by docosane, tricosane, heneicosane, hexatriacontane and tetracosane, which may be grouped as favourable hydrocarbons showing varying levels of kairomonal activity for T. brasiliensis, as compared to eicosane, pentadecane, octacosane and heptadecane, which can be grouped as non-favourable hydrocarbons. In the case of T. exiguum, pentacosane-treated egg cards showed maximum parasitism followed by hexacosane, pentadecane, hexatriacontane, tricosane and docosane thereby indicating their kairomonal activity in comparison with heptadecane, tetracosane, eicosane, heneiocosane and octacosane which recorded low levels of parasitism. In the case of T. brasiliesnsis, tetracosane recorded the highest response at the lowest concentration, C1 (62.5 ng/cm2), which decreased as the concentration increased. Eicosane, heneicosane and docosane recorded the highest parasitism at C2 (125 ng/cm2). In heptadecane, tricosane, pentacosane and hexatriacontane the highest parasitism was recorded at the medium concentration, C3 (250 ng/cm2). Octacosane recorded the highest response at C4 (375 ng/cm2). Pentadecane and hexacosane-treated egg cards showed their highest response at C5 (500 ng/cm2). In the case of T. exiguum, the lowest concentration, C1 evoked the highest response in hexacosane, whereas heptacosane, heneiocosane, docosane and tetracosane recorded the highest parasitism at C2. Eicosane, pentacosane and octacosane recorded maximum parasitism, at C3, whereas tricosane and hexatriacontane showed maximum parasitism at C4 and pentadecane at C5. These concentrations can be taken as the optimum concentration to increase parasitization by these parasitoids. The favourable hydrocarbons at their optimum concentration can be used for efficient management of these parasitoids in field releases. [source] | ||||||||||