An official website of the United States government
Invasive parasites are a major threat to biodiversity worldwide, so understanding the factors that control them is necessary to improve the health of affected host species. In the Galápagos Islands, the invasive nest ectoparasite, the avian vampire fly (Philornis downsi), is causing up to 100% mortality in nestling Darwin’s finches. However, urban finch nests have fewer flies than non-urban finch nests. One explanation is that finches incorporate cigarette butts into their nests, which can decrease nest parasite abundance for other bird species. For our study, we exposed larval flies to cigarette tobacco-treated (concentrated or diluted) or untreated cotton, then characterized pupation success, pupal deformities and success, and adult fly eclosure success and size. The influence of moisture on the effect of tobacco treatment on fly health was also determined. Flies reared in the tobacco treatments as larvae had lower pupation success, larger pupal volume, and a higher prevalence of pupal deformities compared to control flies, regardless of moisture treatment. Furthermore, we found that tobacco-treated flies had lower eclosure success. In fact, very few tobacco-treated flies survived to adulthood. We also collected finch nests and quantified the prevalence and mass of cigarette butts and abundance of flies in the nests. Although most urban finch nests contain cigarette butts (73%), the mass of cigarette butts was very low and did not correlate with fly abundance. Compared to past studies, finch nests require ten times as many cigarette butts to affect fly survival. Although tobacco can negatively affect vampire flies, finches likely do not incorporate enough cigarette butts to affect fly fitness.
more »
« less
Resource competition affects developmental outcomes of the acoustic parasitoid fly Ormia ochracea
Abstract In parasitoid systems, resource competition can significantly impact developmental outcomes. This study investigates how larval competition and host characteristics influence development in the acoustic parasitoid fly Ormia ochracea, using the house cricket Acheta domesticus as a host. We experimentally manipulated larval load (1 vs. 2 larvae per host) and recorded host sex and size to assess their effects on pupation and eclosion (adult hatching) success, as well as pupal and adult fly size. While double infestations increased total yield (0.78 vs. 0.54 flies per host), larvae developing without competition exhibited higher relative pupation and eclosion success and produced larger pupae and adult flies, indicating greater individual fitness. Although female host crickets yielded larger pupae, resource competition was the dominant factor shaping developmental outcomes. These results highlight the trade-offs between reproductive yield and offspring fitness driven by resource competition and validate the commercially available A. domesticus as a viable host.
more »
« less
- Award ID(s):
- 2144831
- PAR ID:
- 10614456
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Annals of the Entomological Society of America
- Volume:
- 118
- Issue:
- 4
- ISSN:
- 0013-8746
- Format(s):
- Medium: X Size: p. 303-314
- Size(s):
- p. 303-314
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Schilder, Rudolf (Ed.)Abstract Parasitoids comprise a speciose insect group, displaying a wide array of life history strategies. In the Pacific Northwest of the United States, the tephritid fruit flies Rhagoletis tabellaria (Fitch) and Rhagoletis indifferens Curran infest red osier dogwood, Cornus sericea L. (Cornaceae), and bitter cherry, Prunus emarginata (Douglas ex Hooker) Eaton (Rosaceae), respectively. The flies are parasitized by different braconid wasps at different life stages; Utetes tabellariae (Fischer) oviposits into R. tabellaria eggs, whereas Diachasma muliebre (Muesebeck) oviposits into R. indifferens larvae feeding in cherries. Because Rhagoletis only have one major generation a year and the wasps attack temporally distinct fly life stages, we predicted that eclosion times of U. tabellariae should more closely follow that of its host than the larval-attacking D. muliebre. As predicted, U. tabellariae eclosed on average 6.0–12.5 d later than R. tabellaria, whereas D. muliebre eclosed on average 32.1 d after R. indifferens. Unexpectedly, however, longer chill duration differentially affected the systems; longer overwinters minimally influenced eclosion times of R. tabellaria and U. tabellariae but caused earlier eclosion of both R. indifferens and D. muliebre. Results imply that in temperate regions, diapause timing in braconid wasps evolves in response to both host life stage attacked and fly eclosion characteristics, possibly reflecting differential effects of winter on host plant fruiting phenology. Differences in phenological sensitivity of the lower host plant trophic level to variation in environmental conditions may have cascading effects, sequentially and differentially affecting eclosion times in higher frugivore (fly) and parasitoid (wasp) trophic levels.more » « less
-
Abstract Eclosion times and rates of Rhagoletis tabellaria (Fitch) (Diptera: Tephritidae) and its parasitoid wasp Utetes tabellariae (Fischer) (Hymenoptera: Braconidae) held at different chilling durations were determined in the laboratory. Adult fly and wasp longevity were also determined. Adult female and male flies from R. tabellaria puparia chilled for 195 days at 4.8 °C and then held at 23.2 °C eclosed on average earlier than U. tabellariae reared from R. tabellaria puparia. Rhagoletis tabellaria also eclosed significantly earlier from puparia chilled for 150 days than 120 days at 2.7 °C, but U. tabellariae eclosion from the two treatments did not differ significantly. Rhagoletis tabellaria eclosion rates were greater with longer chill durations, but U. tabellariae eclosion rates per R. tabellaria puparium did not differ among chill durations. No R. tabellaria eclosed from nonchilled puparia held at 20–22 °C, but at least 18.8% of nonchilled U. tabellariae eclosed. Female and male R. tabellaria on average survived 52.1 and 83.3 days, respectively, while female and male U. tabellariae survived 37.7 and 28.7 days, respectively. Results indicate diapause and developmental traits of R. tabellaria may be more dependent on chilling durations and less flexible than those of U. tabellariae , a wasp that appears adapted to flies in the R. tabellaria species complex.more » « less
-
Parasitoid wasps are exceptionally diverse and use specialized adaptations capable of manipulating the physiology and behaviour of host organisms. In more than two centuries since the first records of Drosophila-parasitizing wasps, nearly 200 described and provisional parasitoid species of drosophilids have been identified. These include endoparasitoids and ectoparasitoids, as well as species attacking larval and pupal hosts. Despite a deep history of research attention and remarkable biodiversity, a wasp species that attacks and develops inside the adult stage of a fly host has not been described previously. Here we report the discovery of a wasp species that infects the adult stage of fruit flies in the genus Drosophila, including one of the most deeply studied model organisms in biology, Drosophila melanogaster. Notably, this wasp can be easily collected from backyard fly baits and has a broad geographic distribution throughout the eastern USA. We document its life history and unique host interactions, including egg-laying into and larval emergence from adult flies, and provide protocols to raise wasps from wild-caught host flies. Our results emphasize the need for ongoing research investment in insect biodiversity and systematics. As parasitoid research continues to uncover unusual biology and supports fundamental mechanistic insights into immunity, metabolism, ecology, evolution and behaviour, we anticipate that this wasp’s association with the laboratory model organism, D. melanogaster, will provide new research opportunities across the life sciences.more » « less
-
NA (Ed.)Antagonistic species relationships such as parasitoid/host interactions lead to evolutionary arms races between species. Many parasitoids use more than one host species, requiring the parasitoid to adapt to multiple hosts, sometimes being the leader or the follower in the evolutionary back-and-forth between species. Thus, multi-species interactions are dynamic and show temporary evolutionary outcomes at a given point in time. We investigated the interactions of the multivoltine parasitoid fly Ormia lineifrons that uses different katydid hosts for each of its fly generations sequentially over time. We hypothesized that this fly is adapted to utilizing all hosts equally well for the population to persist. We quantified and compared the fly’s development in each of the four Neoconocephalus hosts. Cumulative parasitism rates ranged between ~14% and 73%, but parasitoid load and development time did not differ across host species. Yet, pupal size was lowest for flies using N. velox as a host compared to N. triops and other host species. Successful development from pupa to adult fly differed across host species, with flies emerging from N. triops displaying a significantly lower development success rate than those emerging from N. velox and the other two hosts. Interestingly, N. triops and N. velox did not differ in size and were smaller than N. robustus and N. nebrascensis hosts. Thus, O. lineifrons utilized all hosts but displayed especially low ability to develop in N. triops, potentially due to differences in the nutritional status of the host. In the multi-species interactions between the fly and its hosts, the poor use of N. triops may currently affect the fly’s evolution the most. Similarities and differences across host utilization and their evolutionary background are discussed.more » « less
