scholarly journals The effect of nest temperature on growth and survival in juvenile Great Tits Parus major

2021 ◽  
Author(s):  
Alejandro Corregidor‐Castro ◽  
Owen R. Jones

2019 ◽  
Vol 30 (4) ◽  
pp. 1123-1135 ◽  
Author(s):  
Ariane Mutzel ◽  
Anne-Lise Olsen ◽  
Kimberley J Mathot ◽  
Yimen G Araya-Ajoy ◽  
Marion Nicolaus ◽  
...  

AbstractParental provisioning behavior is a major determinant of offspring growth and survival, but high provisioning rates might come at the cost of increased predation threat. Parents should thus adjust provisioning activity according to current predation threat levels. Moreover, life-history theory predicts that response to predation threat should be correlated with investment in current reproduction. We experimentally manipulated perceived predation threat in free-living great tits (Parus major) by presenting parents with a nest predator model while monitoring different aspects of provisioning behavior and nestling begging. Experiments were conducted in 2 years differing greatly in ecological conditions, including food availability. We further quantified male territorial aggressiveness and male and female exploratory tendency. Parents adjusted provisioning according to current levels of threat in an apparently adaptive way. They delayed nest visits during periods of elevated perceived predation threat and subsequently compensated for lost feeding opportunities by increasing provisioning once the immediate threat had diminished. Nestling begging increased after elevated levels of predation threat, but returned to baseline levels by the end of the experiment, suggesting that parents had fully compensated for lost feeding opportunities. There was no evidence for a link between male exploration behavior or aggressiveness and provisioning behavior. In contrast, fast-exploring females provisioned at higher rates, but only in the year with poor environmental conditions, which might indicate a greater willingness to invest in current reproduction in general. Future work should assess whether these personality-related differences in delivery rates under harsher conditions came at a cost of reduced residual reproductive value.



2015 ◽  
Vol 28 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Tanya M. Haupt ◽  
Brent J. Sinclair ◽  
Justine D. Shaw ◽  
Steven L. Chown

AbstractOn sub-Antarctic Marion Island, wandering albatross (Diomedea exulans) nests support high abundances of tineid moth,Pringleophaga marioni, caterpillars. Previous work proposed that the birds serve as thermal ecosystem engineers by elevating nest temperatures relative to ambient, thereby promoting growth and survival of the caterpillars. However, only 17 days of temperature data were presented previously, despite year-long nest occupation by birds. Previous sampling was also restricted to old and recently failed nests, though nests from which chicks have recently fledged are key to understanding how the engineering effect is realized. Here we build on previous work by providing nest temperature data for a full year and by sampling all three nest types. For the full duration of nest occupancy, temperatures within occupied nests are significantly higher, consistently byc. 7°C, than those in surrounding soils and abandoned nests, declining noticeably when chicks fledge. Caterpillar abundance is significantly higher in new nests compared to nests from which chicks have fledged, which in turn have higher caterpillar abundances than old nests. Combined with recent information on the life history ofP. marioni, our data suggest that caterpillars are incidentally added to the nests during nest construction, and subsequently benefit from an engineering effect.



2012 ◽  
Vol 2 (7) ◽  
pp. 529-530
Author(s):  
Jagtap H. S Jagtap H. S ◽  
◽  
S. S. Kulkarni S. S. Kulkarni


2017 ◽  
Vol 11 (3) ◽  
pp. 249
Author(s):  
Lisa Fajar Indriana ◽  
Yuli Afrianti ◽  
Sitti Hilyana ◽  
Muhammad Firdaus Firdaus

Teripang pasir, Holothuria scabra merupakan komoditas hasil laut yang bernilai ekonomis tinggi. Penangkapan berlebihan stok di alam mendorong berkembangnya kegiatan budidaya. Penempelan merupakan fase kritis pada larva teripang karena terjadi peralihan sifat planktonis ke bentik yang memerlukan substrat. Penelitian ini bertujuan untuk mengetahui preferensi penempelan, pertumbuhan, dan sintasan larva H. scabra fase penempelan pada substrat lamun yang berbeda. Penelitian menggunakan metode rancangan acak lengkap dengan perlakuan empat jenis daun lamun berbeda dan lima ulangan. Perlakuan terdiri atas Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), dan Cymodocea rotundata (L-4). Jumlah awal larva sebanyak 1.000 individu dan substrat dirangkai dengan luasan yang sama sebesar 12 cm x 17 cm untuk setiap unit penelitian. Hasil penelitian menunjukkan jenis lamun yang digunakan sebagai substrat berpengaruh secara nyata terhadap preferensi penempelan dan sintasan larva teripang pasir, namun tidak berpengaruh terhadap pertumbuhan. E. acoroides menunjukkan hasil terbaik dengan preferensi penempelan 0,26 ind. cm-2 dan sintasan 10,66%; sehingga layak digunakan sebagai substrat penempelan dalam pembenihan teripang pasir, H. scabra.Holothuria scabra larvae on different seagrass substrates. By: Lisa Fajar Indriana, Yuli Afrianti, Sitti Hilyana, and Muhammad FirdausSandfish Holothuria scabra is marine commodities with a high economic value. Overfishing of natural stocks has compelled an interest to begin aquaculture practice. Settlement is a critical phase for the planktonic larvae as they will transform to benthic form in the presence of substrate. This study aims to evaluate the settlement preferences, growth, and survival rate of H. scabra larvae settled on different seagrass leaves. The research was conducted using the Completely randomized design with four different species of seagrass leaves and five replications. The treatments consist of Enhalus acoroides (L-1), Syringodium isoetifolium (L-2), Cymodocea serrulata (L-3), and Cymodocea rotundata (L-4). Initial number of larvae was 1,000 individuals and the substrate was set with same widthof 12 cm x 17 cm for each unit. Results of the experiment indicated that settlement preference and survival rate of H. scabra larvae was significantly affected by seagrass used as substrate while no significantly differences was observed for growth of larvae. E. acoroides showed the best result with 0.26 ind. cm-2 settelement preference and 10.66% survival rate, so that suitable to be used as settlement substrate in H. scabra hatchery.



2019 ◽  
Vol 118 (8) ◽  
pp. 172-189
Author(s):  
Magreth B Tjizumaue ◽  
Krishna Govender

Due to the absence of appropriate Consumer Protection legislation in Namibia, there seems to be a lack of consumer protection, which may result in consumers being exploited. Since the literature reveals that Consumer Awareness, Consumer Protection, Service Quality and Customer Satisfaction influence Customer Loyalty, the aforementioned relationship was explored among consumers of long-term insurance products in Namibia. The researcher embedded the study in the Services Marketing and User’s Satisfaction/Dissatisfaction theory and developed a framework for creating a more aware consumer and thus contribute to the growth and survival of the long-term insurance industry in Namibia.  A survey was conducted using a questionnaire, among a judgmental sample of 407 long-term insurance consumers in Namibia and Structural Equation Modelling was used to analyse (eight) hypothesized relationships among the research constructs alluded to in the title of this study. In summary, it was ascertained that if the customers are fully aware (have sufficient knowledge of the products and their consumer rights), they will feel protected against unfair business practices. Furthermore, if they perceive having received quality services, they are more likely to be satisfied with the service provider and will therefore, remain loyal.



2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Muhammad Atilah Setiawan ◽  
Muarif Muarif ◽  
Fia Sri Mumpuni

The aim of this study was to determine the growth and survival rate of Ctenopoma fish seeds. This study used a completely randomized design with 3 treatments and 3 replications. The treatment in this study was a different feeding rate using natural feed of Tubifex sp  namely A (8%), B (10%), and C (12%) ). The test fish used was Ctenopoma fish seeds with an initial length of 2.40 ± 0.10 cm and an initial weight of 0.32 ± 0.05 g. Fish seeds are cultivated  for 28 days with feeding frequency twice a day. The results of research showed that the use of different feeding rate had an significantly different (P<0.05) on the specific growth  rate and absolute length growth with the best results in the treatment C. The survival rate was not significantly different between treatments (P>0.05). Key Words: Ctenopoma, feeding rate, growth, survival rate 







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