Life-history evolution in hymenopteran parasitoids : the roles of host and climate

In this thesis I studied the relationships between parasitoids, hosts and climate from an evolutionary point of view by using hymenopteran parasitoids as a model system. A comparative approach was used to study the variation in life-history traits of species or populations from different habitats. I showed that closely related species manipulate their host behaviour differently and allocate their essential resources to different life-history traits during development. Metabolic rate and energy reserves varied strongly between species. At the population level, energy reserves were found differ substantially between different climate zones. A molecular study revealed clear genetic divergence of these populations, which partially reflected the pattern in life-history variation. To conclude, I suggest that life-history traits of parasitoids are subject to natural selection pressures from both host and cli mate. Resource allocation and host manipulation in parasitoids is species specific and highly diverged among populations to fit habitat requirements.LEI Universiteit LeidenAnimal science

Genetic structure of Leptopilina boulardi populations from different climatic zones of Iran

<p>Abstract</p> <p>Background</p> <p>The genetic structure of populations can be influenced by geographic isolation (including physical distance) and ecology. We examined these effects in <it>Leptopilina boulardi</it>, a parasitoid of <it>Drosophila </it>of African origin and widely distributed over temperate and (sub) tropical climates.</p> <p>Results</p> <p>We sampled 11 populations of <it>L. boulardi </it>from five climatic zones in Iran and measured genetic differentiation at nuclear (Amplified Fragment Length Polymorphism; AFLP) and mitochondrial (Cytochrome Oxidase I; COI) loci. An Analysis of Molecular Variance (AMOVA) for the AFLP data revealed that 67.45% of variation resided between populations. No significant variation was observed between climatic zones. However, a significant difference was detected between populations from the central (dry) regions and those from the wetter north, which are separated by desert. A similarly clear cut genetic differentiation between populations from the central part of Iran and those from the north was observed by UPGMA cluster analysis and Principal Coordinates Analysis (PCO). Both UPGMA and PCO further separated two populations from the very humid western Caspian Sea coast (zone 3) from other northern populations from the temperate Caspian Sea coastal plain (zone 2), which are connected by forest. One population (Nour) was genetically intermediate between these two zones, indicating some gene flow between these two groups of populations. In all analyses a mountain population, Sorkhabad was found to be genetically identical to those from the nearby coastal plain (zone 2), which indicates high gene flow between these populations over a short geographical distance. One population from the Caspian coast (Astaneh) was genetically highly diverged from all other populations. A partial Mantel test showed a highly significant positive correlation between genetic and geographic distances, as well as separation by the deserts of central Iran. The COI sequences were highly conserved among all populations.</p> <p>Conclusion</p> <p>The Iranian populations of <it>L. boulardi </it>showed clear genetic structure in AFLP profiles, but not in COI sequence data. The transfer of fruits containing <it>Drosophila </it>larvae parasitized by <it>L. boulardi </it>appears to have caused some unexpected gene flow and changed the genetic composition of populations, particularly in urban areas. Nevertheless, our results suggest that climate, geographic distance and physical barriers may all have contributed to the formation of genetically distinct populations of <it>L. boulardi</it>. Inevitably, there will be overlap between the portions of variance explained by these variables. Disentangling the relative contributions of climate and geography to the genetic structure of this species will require additional sampling.</p

A contribution to the knowledge of Belytinae (Hymenoptera: Diapriidae) in Hyrcanian forests, with the first record of five genera and species from Iran

A faunistic survey of the subfamily Belytinae (Hymenoptera: Diaprioidea, Diapriidae) was carried out in northern Iran during 2010-2018. Based on the specimens collected from Golestan, Guilan, and Mazandarean provinces, five genera Diphora Foerster, 1856, Acanosema Kieffer, 1908, Acanopsilus Kieffer, 1908; Psilomma Foerster, 1856 and Synacra Foerster, 1856, are recorded for the first time from Iran. Each genus is represented by one newly recorded species. Diagnostic characters of the newly recorded taxa are provided along with illustrations. A key to the genera of the subfamily Belytinae from Iran is presented

High Hemocyte Load Is Associated with Increased Resistance against Parasitoids in Drosophila suzukii, a Relative of D. melanogaster

Among the most common parasites of Drosophila in nature are parasitoid wasps, which lay their eggs in fly larvae and pupae. D. melanogaster larvae can mount a cellular immune response against wasp eggs, but female wasps inject venom along with their eggs to block this immune response. Genetic variation in flies for immune resistance against wasps and genetic variation in wasps for virulence against flies largely determines the outcome of any fly-wasp interaction. Interestingly, up to 90% of the variation in fly resistance against wasp parasitism has been linked to a very simple mechanism: flies with increased constitutive blood cell (hemocyte) production are more resistant. However, this relationship has not been tested for Drosophila hosts outside of the melanogaster subgroup, nor has it been tested across a diversity of parasitoid wasp species and strains. We compared hemocyte levels in two fly species from different subgroups, D. melanogaster and D. suzukii, and found that D. suzukii constitutively produces up to five times more hemocytes than D. melanogaster. Using a panel of 24 parasitoid wasp strains representing fifteen species, four families, and multiple virulence strategies, we found that D. suzukii was significantly more resistant to wasp parasitism than D. melanogaster. Thus, our data suggest that the relationship between hemocyte production and wasp resistance is general. However, at least one sympatric wasp species was a highly successful infector of D. suzukii, suggesting specialists can overcome the general resistance afforded to hosts by excessive hemocyte production. Given that D. suzukii is an emerging agricultural pest, identification of the few parasitoid wasps that successfully infect D. suzukii may have value for biocontrol

Indoor environment assessment of special wards of educational hospitals for the detection of fungal contamination sources: A multi-center study (2019-2021)

Background and Purpose: The hospital environment was reported as a real habitat for different microorganisms, especially mold fungi. On the other hand, these opportunistic fungi were considered hospital-acquired mold infections in patients with weak immune status. Therefore, this multi-center study aimed to evaluate 23 hospitals in 18 provinces of Iran for fungal contamination sources.Materials and Methods: In total, 43 opened Petri plates and 213 surface samples were collected throughout different wards of 23 hospitals. All collected samples were inoculated into Sabouraud Dextrose Agar containing Chloramphenicol (SC), and the plates were then incubated at 27-30ºC for 7-14 days.Results: A total of 210 fungal colonies from equipment (162, 77.1%) and air (48,22.9%) were identified. The most predominant isolated genus was Aspergillus (47.5%),followed by Rhizopus (14.2%), Mucor (11.7%), and Cladosporium (9.2%). Aspergillus(39.5%), Cladosporium (16.6%), as well as Penicillium and Sterile hyphae (10.4% each), were the most isolates from the air samples. Moreover, intensive care units (38.5%) and operating rooms (21.9%) had the highest number of isolated fungal colonies. Out of 256 collected samples from equipment and air, 163 (63.7%) were positive for fungal growth.The rate of fungal contamination in instrument and air samples was 128/213 (60.1%) and 35/43 (81.2%), respectively. Among the isolated species of Aspergillus, A. flavus complex (38/96, 39.6%), A. niger complex (31/96, 32.3%), and A. fumigatus complex (15/96, 15.6%) were the commonest species.Conclusion: According to our findings, in addition to air, equipment and instrument should be considered among the significant sources of fungal contamination in the indoor environment of hospitals. Airborne fungi, Hospital, Indoor air, Equipment, Sources of fungal contamination in the indoor environment of hospitals

Life-history evolution in hymenopteran parasitoids : the roles of host and climate

In this thesis I studied the relationships between parasitoids, hosts and climate from an evolutionary point of view by using hymenopteran parasitoids as a model system. A comparative approach was used to study the variation in life-history traits of species or populations from different habitats. I showed that closely related species manipulate their host behaviour differently and allocate their essential resources to different life-history traits during development. Metabolic rate and energy reserves varied strongly between species. At the population level, energy reserves were found differ substantially between different climate zones. A molecular study revealed clear genetic divergence of these populations, which partially reflected the pattern in life-history variation. To conclude, I suggest that life-history traits of parasitoids are subject to natural selection pressures from both host and cli mate. Resource allocation and host manipulation in parasitoids is species specific and highly diverged among populations to fit habitat requirements.</p

Metabolic rate affects adult life span independently of developmental rate in parasitoid wasps

Developmental time and body size correlate with lifespan in a wide range of taxa, although not in insect parasitoids. When the rate of development is independent of adult metabolic rate, adult lifespan is free to adapt to the adult environment. We suggest that interspecific variation in intrinsic adult metabolic rates, differences in allocation of lipids to longevity, and reproduction and differences in the ability to use carbohydrates as an adult should all result in variation of adult lifespan, independent of development time. To test these ideas, we measured metabolic rate, lipid content and egg load at eclosion, developmental time, and lifespan of females with and without carbohydrate food in five species of Asobara, which represent parasitoids of Drosophila. No relationship between development time and adult longevity was found. As predicted, metabolic rates varied between species and appeared to trade off with adult longevity. We found no clear link between initial egg load and the longevity of a species, suggesting that lipid allocation may be less important in determining adult lifespan. The results obtained indicate that differences in metabolic rate have an important effect on adult lifespan, without affecting developmental rate in parasitoids