TY - JOUR
T1 - Non-native insects dominate daytime pollination in a high-elevation Hawaiian dryland ecosystem
AU - Aslan, Clare E.
AU - Shiels, Aaron B.
AU - Haines, William
AU - Liang, Christina T.
N1 - Funding Information:
The authors thank H. Coad, M. Donofrio, J. Felt, J. Smith, and A. Wagner for tireless hours of field observations, as well as the PTA Natural Resources Office for essential logistical support and assistance. This work was funded by the Department of Defense Strategic Environmental Research and Development Program (grant no. RC-2432) and was performed under USFWS Native Endangered Species Recovery Permit: TE-28360B-0; Hawaii DLNR-DOFAW Permit for Threatened & Endangered Plant Species: P-201; and Hawaii DLNR-DOFAW Permit for Native Invertebrate Research: FHM17-428. The authors thank K. Magnacca for invaluable bee identification assistance and two anonymous reviewers for insightful and very helpful recommendations.
Publisher Copyright:
© 2019 Botanical Society of America
PY - 2019/2/1
Y1 - 2019/2/1
N2 - Premise of the Study: Over one-third of the native flowering plant species in the Hawaiian Islands are listed as federally threatened or endangered. Lack of sufficient pollination could contribute to reductions in populations, reproduction, and genetic diversity among these species but has been little studied. Methods: We used systematic observations and manual flower treatments to quantify flower visitation and outcrossing dependency of eight native (including four endangered) plant species in a dryland ecosystem in Hawaii: Argemone glauca, Bidens menziesii, Dubautia linearis, Haplostachys haplostachya, Sida fallax, Silene lanceolata, Stenogyne angustifolia, and Tetramolopium arenarium. Key Results: During 576.36 h of flower observations, only insects visited the flowers. Out of all recorded flower visits, 85% were performed by non-native species, particularly the honeybee (Apis mellifera) and flies in the family Syrphidae. Some plant species received little visitation (e.g., S. angustifolia received one visit in 120 h of observation), whereas others were visited by a wide diversity of insects. The endangered plant species were visited by fewer visitor taxa than were the common native plant species. For six of the focal plant species, bagging of flowers to exclude pollinators resulted in significant reductions in seed set. Conclusions: The flower visitor community in this system, although heavily dominated by non-native insects, appears to be facilitating pollination for multiple plant species. Non-native insects may thus be sustaining biotic interactions otherwise threatened with disruption in this island ecosystem. This may be particularly important for the studied endangered plant species, which exhibit fewer partners than the more common plant species.
AB - Premise of the Study: Over one-third of the native flowering plant species in the Hawaiian Islands are listed as federally threatened or endangered. Lack of sufficient pollination could contribute to reductions in populations, reproduction, and genetic diversity among these species but has been little studied. Methods: We used systematic observations and manual flower treatments to quantify flower visitation and outcrossing dependency of eight native (including four endangered) plant species in a dryland ecosystem in Hawaii: Argemone glauca, Bidens menziesii, Dubautia linearis, Haplostachys haplostachya, Sida fallax, Silene lanceolata, Stenogyne angustifolia, and Tetramolopium arenarium. Key Results: During 576.36 h of flower observations, only insects visited the flowers. Out of all recorded flower visits, 85% were performed by non-native species, particularly the honeybee (Apis mellifera) and flies in the family Syrphidae. Some plant species received little visitation (e.g., S. angustifolia received one visit in 120 h of observation), whereas others were visited by a wide diversity of insects. The endangered plant species were visited by fewer visitor taxa than were the common native plant species. For six of the focal plant species, bagging of flowers to exclude pollinators resulted in significant reductions in seed set. Conclusions: The flower visitor community in this system, although heavily dominated by non-native insects, appears to be facilitating pollination for multiple plant species. Non-native insects may thus be sustaining biotic interactions otherwise threatened with disruption in this island ecosystem. This may be particularly important for the studied endangered plant species, which exhibit fewer partners than the more common plant species.
KW - Apis mellifera
KW - Asteraceae
KW - Haplostachys haplostachya
KW - Silene lanceolata
KW - Stenogyne angustifolia
KW - Tetramolopium arenarium
KW - disrupted mutualism
KW - flower pollination treatments
KW - flower visitation observations
KW - island endemics
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U2 - 10.1002/ajb2.1233
DO - 10.1002/ajb2.1233
M3 - Article
C2 - 30768870
AN - SCOPUS:85061568691
SN - 0002-9122
VL - 106
SP - 313
EP - 324
JO - American Journal of Botany
JF - American Journal of Botany
IS - 2
ER -