Bird song is used for mate attraction and is important for establishing reproductive isolation. Current research highlights performance constraints on song production that may be influenced by variation in bill morpho...Bird song is used for mate attraction and is important for establishing reproductive isolation. Current research highlights performance constraints on song production that may be influenced by variation in bill morphology. Darwin＇s finches are a model system for studying the relationship between morphology and song performance, with previous studies suggesting that lower vocal performance is correlated with larger bill size. Here, we tested for a relationship between bill morphology and vocal performance in Darwin＇s Small Tree Finch （Camarhynchus parvulus） on Floreana Island. We found no evidence of a correlation between bill morphology and vocal performance. This finding is in agreement with prior study of the Small Tree Finch, but contrasts a greater body of work addressing song in Darwin＇s Finches. We discussed our findings in the context of ecological divergence, and ecological variation across species.展开更多
The conservation behavior framework is useful to identify key linkages between behavior and conservation practice. We apply this framework to a novel host-parasite system on the Galapagos Islands and ask if there have...The conservation behavior framework is useful to identify key linkages between behavior and conservation practice. We apply this framework to a novel host-parasite system on the Galapagos Islands and ask if there have been changes in parasite oviposition behavior and host mortality patterns across the first decade （2004-2013） of its known association. The Dipteran parasite Philornis downsi was first discovered in Darwin＇s finch nests in 1997 and is the biggest threat to the survival of Galapagos land birds. Host mortality has increased over the past decade. In Dipterans, pupation and pupae size are determined by access to host resources. Here, we test the hypothesis that P downsi flies are laying eggs in finch nests earlier in the nestling phase to maximize larval feeding time and therefore chance of pupation success before host death. The results show fewer 1st instar larvae later in the host nesting cycle in support of earlier egg laying behavior by female flies. Between 2004 and 2013, parasite intensity increased from -28 to -48 parasites per nest, host mortality increased from -50% to -90%, and host age at death decreased from -11 to -5 days. The earlier age at host death was correlated with fewer pupae （from -50% to -20%） and smaller pupae size （-10% decrease）. Changes in parasite behavior reveal new fitness costs to both the parasite and Darwin＇s finches. These findings un- derscore the need for urgent conservation action to save Darwin＇s finches from extinction due to a novel, lethal and introduced parasite [Current Zoology 60 （4）： 542-550, 2014].展开更多
基金funded by Flinders University (Research Establishment Grant to SK, Overseas Field Trip Grant to RC), Conservation International and the American Bird Conservancy with awards to SK,and the Australian Federation of University Women SA with a Barbara Crase Bursary to RC
文摘Bird song is used for mate attraction and is important for establishing reproductive isolation. Current research highlights performance constraints on song production that may be influenced by variation in bill morphology. Darwin＇s finches are a model system for studying the relationship between morphology and song performance, with previous studies suggesting that lower vocal performance is correlated with larger bill size. Here, we tested for a relationship between bill morphology and vocal performance in Darwin＇s Small Tree Finch （Camarhynchus parvulus） on Floreana Island. We found no evidence of a correlation between bill morphology and vocal performance. This finding is in agreement with prior study of the Small Tree Finch, but contrasts a greater body of work addressing song in Darwin＇s Finches. We discussed our findings in the context of ecological divergence, and ecological variation across species.
文摘The conservation behavior framework is useful to identify key linkages between behavior and conservation practice. We apply this framework to a novel host-parasite system on the Galapagos Islands and ask if there have been changes in parasite oviposition behavior and host mortality patterns across the first decade （2004-2013） of its known association. The Dipteran parasite Philornis downsi was first discovered in Darwin＇s finch nests in 1997 and is the biggest threat to the survival of Galapagos land birds. Host mortality has increased over the past decade. In Dipterans, pupation and pupae size are determined by access to host resources. Here, we test the hypothesis that P downsi flies are laying eggs in finch nests earlier in the nestling phase to maximize larval feeding time and therefore chance of pupation success before host death. The results show fewer 1st instar larvae later in the host nesting cycle in support of earlier egg laying behavior by female flies. Between 2004 and 2013, parasite intensity increased from -28 to -48 parasites per nest, host mortality increased from -50% to -90%, and host age at death decreased from -11 to -5 days. The earlier age at host death was correlated with fewer pupae （from -50% to -20%） and smaller pupae size （-10% decrease）. Changes in parasite behavior reveal new fitness costs to both the parasite and Darwin＇s finches. These findings un- derscore the need for urgent conservation action to save Darwin＇s finches from extinction due to a novel, lethal and introduced parasite [Current Zoology 60 （4）： 542-550, 2014].
