Search results for "Wasp"
showing 10 items of 102 documents
Foraging behavior of two egg parasitoids exploiting chemical cues from the stink bug Piezodorus guildinii (Hemiptera: Pentatomidae).
2019
Several parasitoids attacking the same host may lead to competition. Adult parasitoids' abilities to find, parasitize and defend hosts determine resource's retention potential. In soybean, two egg parasitoid species, Telenomus podisi and Trissolcus urichi (Hymenoptera: Platygastridae), compete on the egg masses of Piezodorus guildinii (Hemiptera: Pentatomidae) one of the major pest of this crop. We evaluated parasitoid's abilities to exploit hosts' footprints; and parasitoid's behavior when competing for the same host. Both arena residence time and retention time were similar for T. podisi and T. urichi on male or female host footprints. In its turn, T. urichi reentered the area contaminate…
Fitness costs of intrinsic competition in two egg parasitoids of a true bug
2015
Intrinsic competition in insect parasitoids occurs when supernumerary larvae develop in the same host as consequence of multiple ovipositions by females of the same species (intra-specific competition) or by females of different species (inter-specific competition). Studies on intrinsic competition have mainly focused on understanding the factors that play a role in the outcome of competition, while fitness-related effects for the parasitoid surviving the competition have been poorly investigated, especially in egg parasitoids. Interestingly, even the winning parasitoid can experience fitness costs due to larval development in a host in which multiple factors have been injected by the ovipo…
Low parasitism rates in parthenogenetic bagworm moths do not support the parasitoid hypothesis for sex
2012
The parasite hypothesis for sex is one of the many theories that have been suggested to solve the mystery of the widespread occurrence of sex despite its high short-term costs. It suggests that sexual lineages have an evolutionary advantage over parthenogens because they can frequently generate new genotypes that are temporarily less prone to coevolving parasites. In this study, we looked for further supporting evidence for the parasite hypothesis of sex in an attempt to understand the coexistence of sexual and parthenogenetic bagworm moths (Naryciinae). The bagworm moths and their parasitoids form one of the few natural host-parasite systems where sexual and parthenogenetic hosts are appar…
High Temperatures Result in Smaller Nurseries which Lower Reproduction of Pollinators and Parasites in a Brood Site Pollination Mutualism
2014
In a nursery pollination mutualism, we asked whether environmental factors affected reproduction of mutualistic pollinators, non-mutualistic parasites and seed production via seasonal changes in plant traits such as inflorescence size and within-tree reproductive phenology. We examined seasonal variation in reproduction in Ficus racemosa community members that utilise enclosed inflorescences called syconia as nurseries. Temperature, relative humidity and rainfall defined four seasons: winter; hot days, cold nights; summer and wet seasons. Syconium volumes were highest in winter and lowest in summer, and affected syconium contents positively across all seasons. Greater transpiration from the…
Comparative morphology of the postpharyngeal gland in the Philanthinae (Hymenoptera, Crabronidae) and the evolution of an antimicrobial brood protect…
2015
Background Hymenoptera that mass-provision their offspring have evolved elaborate antimicrobial strategies to ward off fungal infestation of the highly nutritive larval food. Females of the Afro-European Philanthus triangulum and the South American Trachypus elongatus (Crabronidae, Philanthinae) embalm their prey, paralyzed bees, with a secretion from a complex postpharyngeal gland (PPG). This coating consists of mainly unsaturated hydrocarbons and reduces water accumulation on the prey’s surface, thus rendering it unfavorable for fungal growth. Here we (1) investigated whether a North American Philanthus species also employs prey embalming and (2) assessed the occurrence and morphology of …
Inhibition of FcεRI-mediated Activation of Rat Basophilic Leukemia Cells by Clostridium difficile Toxin B (Monoglucosyltransferase)
1996
Abstract Treatment of rat basophilic leukemia (RBL) 2H3-hm1 cells with Clostridium difficile toxin B (2 ng/ml), which reportedly depolymerizes the actin cytoskeleton, blocked [3H]serotonin release induced by 2,4-dinitrophenyl-bovine serum albumin, carbachol, mastoparan, and reduced ionophore A23187-stimulated degranulation by about 55-60%. In lysates of RBL cells, toxin B 14C-glucosylated two major and one minor protein. By using two-dimensional gel electrophoresis and immunoblotting, RhoA and Cdc42 were identified as protein substrates of toxin B. In contrast to toxin B, Clostridium botulinum transferase C3 that selectively inactivates RhoA by ADP-ribosylation did not inhibit degranulation…
The Phylogenetic Analysis of Variable-Length Sequence Data: Elongation Factor–1α Introns in European Populations of the Parasitoid Wasp Genus Pauesia…
2001
Elongation factor-1alpha (EF-1alpha) is a highly conserved nuclear coding gene that can be used to investigate recent divergences due to the presence of rapidly evolving introns. However, a universal feature of intron sequences is that even closely related species exhibit insertion and deletion events, which cause variation in the lengths of the sequences. Indels are frequently rich in evolutionary information, but most investigators ignore sites that fall within these variable regions, largely because the analytical tools and theory are not well developed. We examined this problem in the taxonomically problematic parasitoid wasp genus Pauesia (Hymenoptera: Braconidae: Aphidiinae) using con…
FIRST RECORD IN EUROPE OF SEEDLINGS OF FICUS MACROPHYLLA F. COLUMNARIS (Moraceae) AND OF ITS POLLINATING WASP PLEISTODONTES CF. IMPERIALIS (Chalcidoi…
2015
Since the first half of the nineteenth century, several Ficus species have been introduced into Italy as ornamental trees throughout urban gardens and along urban roads. Because a relationship with an agaonid wasp is essential for the pollination and consequently for the production of fertile seeds of Ficus spp., the seedlings of other introduced fig species (Ficus microcarpa L. f., Ficus rubiginosa Desf. ex Vent. and Ficus watkinsiana F.M. Bailey) weren’t found in Europe in conjunction with their pollinating wasps until more than a century after the figs’ introduction. This study presents the first recorded observation of Ficus macrophylla f. columnaris (C. Moore) D. J. Dixon seedlings in …
Cynipid wasps inducing galls on plants of the genus Picris (Asteraceae) in Europe, with a description of a new species of Phanacis Foerster (Hymenopt…
2008
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Immunity and other defenses in pea aphids, Acyrthosiphon pisum
2010
Background Recent genomic analyses of arthropod defense mechanisms suggest conservation of key elements underlying responses to pathogens, parasites and stresses. At the center of pathogen-induced immune responses are signaling pathways triggered by the recognition of fungal, bacterial and viral signatures. These pathways result in the production of response molecules, such as antimicrobial peptides and lysozymes, which degrade or destroy invaders. Using the recently sequenced genome of the pea aphid (Acyrthosiphon pisum), we conducted the first extensive annotation of the immune and stress gene repertoire of a hemipterous insect, which is phylogenetically distantly related to previously ch…