Differential effects of elevated nest temperature and parasitism on the gut microbiota of wild avian hosts

Background Changes in wild animal gut microbiotas may influence host health and fitness. While many studies have shown correlations between gut microbiota structure and external factors, few studies demonstrate causal links between environmental variables and microbiota shifts. Here, we use a fully factorial experiment to test the effects of elevated ambient temperature and natural nest parasitism by nest flies (Protocalliphora sialia) on the gut microbiotas of two species of wild birds, the eastern bluebird (Sialia sialis) and the tree swallow (Tachycineta bicolor). Results We find that bacterial communities from the nestlings of each host species show idiosyncratic responses to both heat and parasitism, with gut microbiotas of eastern bluebirds more disrupted by heat and parasitism than those of tree swallows. Thus, we find that eastern bluebirds are unable to maintain stable associations with their gut bacteria in the face of both elevated temperature and parasitism. In contrast, tree swallow gut microbiotas are not significantly impacted by either heat or nest parasitism. Conclusions Our results suggest that excess heat (e.g., as a result of climate change) may destabilize natural host-parasite-microbiota systems, with the potential to affect host fitness and survival in the Anthropocene.

Differential Effects of Elevated Nest Temperature and Parasitism on the Gut Microbiota of Wild Avian Hosts

Background: Changes in wild animal gut microbiotas may influence host health and fitness. While many studies have shown correlations between gut microbiota structure and external factors, few studies demonstrate causal links between environmental variables and microbiota shifts. Here, we use a fully factorial experiment to test the effects of elevated ambient temperature and natural nest parasitism by nest flies (Protocalliphora sialia) on the microbiotas of two species of wild birds, the eastern bluebird (Sialia sialis) and the tree swallow (Tachycineta bicolor).Results: We find that bacterial communities from the nestlings of each host species show differential response to both heat and parasitism, with gut microbiotas of eastern bluebirds more disrupted by heat and parasitism than those of tree swallows. Thus, we find that eastern bluebirds are unable to maintain stable associations with their gut bacteria in the face of both elevated temperature and parasitism. In contrast, tree swallow gut microbiotas are not significantly impacted by either heat or nest parasitism.Conclusions: Our results suggest that excess heat (e.g., as a result of climate change) may destabilize natural host-parasite-microbiota systems, with the potential to affect host fitness and survival in the anthropocene.

Common Terns Sterna hirundo incubating a Red-necked Grebe Podiceps grisegena egg

During a study of Red-necked Grebes Podiceps grisegena in Lake Slagsmyren, Sweden, a pair of Common Terns Sterna hirundo were observed to have placed their two eggs on a deserted, floating nest of a Red-necked Grebe. Prior to this, the grebes had laid one egg of their own in the nest and this egg was included by the terns in their clutch and incubated by them. The species assignment of the odd egg was confirmed with DNA sequencing. A lack of natural nest sites for the terns to use at the lake could have caused this somewhat unusual choice of a nest site. I discuss possible explanations for adopting a foreign egg, including the adaptive behavioural response to roll an egg into the nest bowl to salvage lost eggs, the incubation stimulus that foreign eggs or egg-like objects potentially provide, and the limited egg discrimination abilities of Common Terns. The incubation of a foreign egg may reasonably be assumed to cost energy but to be of little benefit, if any, to the incubator.

Breeding ecology of the Yellow-bellied Warbler (Abroscopus superciliaris)

The life history of birds dictates their activities and is crucial to population success. However, the life history traits of only one-third of the world’s bird species have been described; the rest are poorly understood. We studied the breeding ecology of the Yellow-bellied Warbler (Abroscopus superciliaris) and documented reproductive information throughout the egg and nestling periods. The data included natural nest sites, nest components, nest size, egg laying dates and time, egg morph, egg size, clutch size, egg incubation, nestling brooding and feeding, nestling morph and growth, and reproductive outcome. This study provided particular information of breeding ecology that has not been reported before in the Yellow-bellied Warbler.

Pengamatan Kesesuaian Lahan Peneluran Penyu Lekang Lepidochelys olivacea, Eschscholtz, 1829 (Reptilia:Cheloniidae) di Pantai Mapak Indah, Nusa Tenggara Barat

ABSTRAK : Pantai Mapak Indah merupakan pantai yang sering menjadi pantai pendaratan biota Penyu, umumnya penyu yang mendarat berjenis penyu Lekang (Lepidochelys olivaceae), pantai yang juga di gunakan untuk aktifitas nelayan dan pariwisata diduga akan mengganggu habitat penyu yang cenderung merusak atau merubahnya. Tujuan dari penelitian ini adalah untuk mengetahui habitat yang sesuai untuk kebutuhan peneluran penyu Lekang (Lepidochelys olivaceae). Metode yang di pakai menggunakan data Primer (Suhu, Kelembaban, Kemiringan, dan Vegetasi) dan skunder berasal dari catatan kelompok pelestari penyu dan instansi terkait. Penelitian ini di laksanakan pada tanggal 24 Juni – 05 Agustus 2019. Hasil dari penelitan ini adalah rentang kemiringan pantai mencapai 10.5%-26% dengan rata-rata 16.3% masih dalam kategori Agak Curam, untuk perbandingan komposisi pasir di sarang Alami dan Semi-Alami 92,94% & 96,34%, vegetasi yang di temukan di sekitar pantai adalah cemara Udang (Casuarina Equisetifolia) dan Pandan Laut (Pandanus sp.), kelapa (Cocos Nucifera) dan Katang-katang (Ipomoea pes-caprae). Suhu saat di lakukan pengamatan selama seminggu memiliki rentang 25°-28° hal ini dapat mempengaruhi jenis kelamin Tukik yang akan menetas serta lama inkubasinya di dalam sarang Semi-Alami ABSTRACT: Mapak Indah Beach is a beach that is often used as a landing site for sea turtles, generally turtles that land on the type of Lekang turtle (Lepidochelys olivaceae), a beach that is also used for fishing and tourism activities is thought to disturb turtle habitats that tend to damage or change it. The purpose of this study was to determine the suitable habitat for the needs of Lekang turtle nesting (Lepidochelys olivaceae). The method used uses Primary data (Temperature, Humidity, Slope, and Vegetation) and secondary data derived from the records of turtle conservation groups and related agencies. This research was carried out on 24 June - 05 August 2019. The results of this research are the range of beach slopes reaching 10.5% -26% with an average of 16.3% still in the category of somewhat steep, for comparison of sand composition in natural and semi-natural nests 92.94% & 96.34%, vegetation found around the coast is pine shrimp (Casuarina Equisetifolia) and Pandan Laut (Pandanus sp.), Coconuts (Cocos Nucifera) and Katang-Katang (Ipomoea pes-caprae). Temperature when observed for a week has a range of 25 ° -28 ° this can affect the sex of the hatchlings that will hatch and the length of incubation in the Semi-Natural nest