Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly
Abstract We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly (Papilio godeffroyi), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During mon...
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Wiley
2024-10-01
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| Series: | Ecosphere |
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| Online Access: | https://doi.org/10.1002/ecs2.70032 |
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| author | Paul C. Banko Mark A. Schmaedick Robert W. Peck Adam C. Miles Niela P. Leifi |
| author_facet | Paul C. Banko Mark A. Schmaedick Robert W. Peck Adam C. Miles Niela P. Leifi |
| author_sort | Paul C. Banko |
| collection | DOAJ |
| description | Abstract We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly (Papilio godeffroyi), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During monthly surveys of its only known host plant, Micromelum minutum, across eight sites in 2013 and 2014, we collected eggs, eggshells, larvae, pupae, and pupal exuviae. Live specimens were reared under laboratory conditions to determine reproductive outcomes, developmental rates, and sex ratios, as well as parasitoid attack frequencies, brood sizes, and sex ratios. Sixty‐six of 448 (14.7%) eggs produced larvae, 47 of which became adults. The sex ratio was approximately even overall and within each developmental stage. Eggs were slightly larger on individual host trees and in host tree stands that yielded more eggs per unit of foliage, indicating that ovipositing females responded to some features of host trees and stands. Eggs hatching female or male larvae were similar in size, and the sexes developed at similar rates. A newly described species of parasitoid wasp, Ooencyrtus pitosina (Encyrtidae), emerged from 73.6% of 382 butterfly eggs that failed to hatch in the laboratory (62.7% of 448 eggs overall). Forty‐one other eggs contained dead parasitoid larvae. An additional, unidentified Ooencyrtus wasp species emerged from a single P. godeffroyi egg. No parasitoids were reared from P. godeffroyi larvae or pupae. Of 656 P. godeffroyi eggshells collected in the field and examined in the laboratory, 62.2% showed signs of having been parasitized by O. pitosina. There was no evidence that parasitism rates were density‐dependent. O. pitosina brood sizes ranged from 1 to 5, with the sex ratio skewed toward females (2.40 F:1.00 M). Larger parasitoid broods were associated with slightly larger host eggs, indicating that female wasps may adjust brood size according to host egg size or that fewer wasp larvae are able to complete development in smaller eggs. Techniques used to rear both P. godeffroyi and O. pitosina in the laboratory could be applied to a captive‐rear, wild‐release program, which may facilitate reestablishment of the species in Samoa. |
| format | Article |
| id | doaj-art-310e2954ac6943149af2977935e1373d |
| institution | OA Journals |
| issn | 2150-8925 |
| language | English |
| publishDate | 2024-10-01 |
| publisher | Wiley |
| record_format | Article |
| series | Ecosphere |
| spelling | doaj-art-310e2954ac6943149af2977935e1373d2025-08-20T02:11:57ZengWileyEcosphere2150-89252024-10-011510n/an/a10.1002/ecs2.70032Reproductive ecology and egg parasitism of the Samoan swallowtail butterflyPaul C. Banko0Mark A. Schmaedick1Robert W. Peck2Adam C. Miles3Niela P. Leifi4U.S. Geological Survey Pacific Island Ecosystems Research Center, Kīlauea Field Station Hawai‘i National Park Hawai‘i USADivision of Agriculture, Community and Natural Resources American Samoa Community College Pago Pago American SamoaHawai‘i Cooperative Studies Unit University of Hawai‘i at Hilo Hawai‘i National Park Hawai‘i USAAmerican Samoa Department of Marine and Wildlife Resources Pago Pago American SamoaDivision of Agriculture, Community and Natural Resources American Samoa Community College Pago Pago American SamoaAbstract We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly (Papilio godeffroyi), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During monthly surveys of its only known host plant, Micromelum minutum, across eight sites in 2013 and 2014, we collected eggs, eggshells, larvae, pupae, and pupal exuviae. Live specimens were reared under laboratory conditions to determine reproductive outcomes, developmental rates, and sex ratios, as well as parasitoid attack frequencies, brood sizes, and sex ratios. Sixty‐six of 448 (14.7%) eggs produced larvae, 47 of which became adults. The sex ratio was approximately even overall and within each developmental stage. Eggs were slightly larger on individual host trees and in host tree stands that yielded more eggs per unit of foliage, indicating that ovipositing females responded to some features of host trees and stands. Eggs hatching female or male larvae were similar in size, and the sexes developed at similar rates. A newly described species of parasitoid wasp, Ooencyrtus pitosina (Encyrtidae), emerged from 73.6% of 382 butterfly eggs that failed to hatch in the laboratory (62.7% of 448 eggs overall). Forty‐one other eggs contained dead parasitoid larvae. An additional, unidentified Ooencyrtus wasp species emerged from a single P. godeffroyi egg. No parasitoids were reared from P. godeffroyi larvae or pupae. Of 656 P. godeffroyi eggshells collected in the field and examined in the laboratory, 62.2% showed signs of having been parasitized by O. pitosina. There was no evidence that parasitism rates were density‐dependent. O. pitosina brood sizes ranged from 1 to 5, with the sex ratio skewed toward females (2.40 F:1.00 M). Larger parasitoid broods were associated with slightly larger host eggs, indicating that female wasps may adjust brood size according to host egg size or that fewer wasp larvae are able to complete development in smaller eggs. Techniques used to rear both P. godeffroyi and O. pitosina in the laboratory could be applied to a captive‐rear, wild‐release program, which may facilitate reestablishment of the species in Samoa.https://doi.org/10.1002/ecs2.70032American Samoabutterfly reproductive ecologyegg parasitismMicromelum minutumOoencyrtus pitosinaPapilio godeffroyi |
| spellingShingle | Paul C. Banko Mark A. Schmaedick Robert W. Peck Adam C. Miles Niela P. Leifi Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly Ecosphere American Samoa butterfly reproductive ecology egg parasitism Micromelum minutum Ooencyrtus pitosina Papilio godeffroyi |
| title | Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly |
| title_full | Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly |
| title_fullStr | Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly |
| title_full_unstemmed | Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly |
| title_short | Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly |
| title_sort | reproductive ecology and egg parasitism of the samoan swallowtail butterfly |
| topic | American Samoa butterfly reproductive ecology egg parasitism Micromelum minutum Ooencyrtus pitosina Papilio godeffroyi |
| url | https://doi.org/10.1002/ecs2.70032 |
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