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151.
Nagy JA Johnson DL Larter NC Campbell MW Derocher AE Kelly A Dumond M Allaire D Croft B 《Ecological applications》2011,21(6):2334-2348
Effective management and conservation of species, subspecies, or ecotypes require an understanding of how populations are structured in space. We used satellite-tracking locations and hierarchical and fuzzy clustering to quantify subpopulations within the behaviorally different barren-ground caribou (Rangifer tarandus groenlandicus), Dolphin and Union island caribou (R. t. groenlandicus x pearyi), and boreal (R. t. caribou) caribou ecotypes in the Northwest Territories and Nunavut, Canada. Using a novel approach, we verified that the previously recognized Cape Bathurst, Bluenose-West, Bluenose-East, Bathurst, Beverly, Qamanirjuaq, and Lorillard barren-ground subpopulations were robust and that the Queen Maude Gulf and Wager Bay barren-ground subpopulations were organized as individuals. Dolphin and Union island and boreal caribou formed one and two distinct subpopulation, respectively, and were organized as individuals. Robust subpopulations were structured by strong annual spatial affiliation among females; subpopulations organized as individuals were structured by migratory connectivity, barriers to movement, and/or habitat discontinuity. One barren-ground subpopulation used two calving grounds, and one calving ground was used by two barren-ground subpopulations, indicating that these caribou cannot be reliably assigned to subpopulations solely by calving-ground use. They should be classified by annual spatial affiliation among females. Annual-range size and path lengths varied significantly among ecotypes, including mountain woodland caribou (R. t. caribou), and reflected behavioral differences. An east-west cline in annual-range sizes and path lengths among migratory barren-ground subpopulations likely reflected differences in subpopulation size and habitat conditions and further supported the subpopulation structure identified. 相似文献
152.
Multiple paternity and individual variation in sperm precedence in the simultaneously hermaphroditic land snail Arianta arbustorum 总被引:2,自引:0,他引:2
Bruno Baurl 《Behavioral ecology and sociobiology》1994,35(6):413-421
Intraspecific variation in the proportion of offspring sired by the second mate with a female (P2) is an aspect of sperm competition that has received little attention. I examined the effects of delay between copulations (range 9–380 days) and size of sperm donor on sperm precedence in double-mated individuals of the simultaneously hermaphroditic land snail Arianta arbustorum. Using shell colour as a genetic marker, paternity was analysed in 132 broods produced by 35 snails that had mated with two partners of different genotype. Sperm precedence (P2) was influenced by the time between the two matings when the mating delay exceeded 70 days (one reproductive season). P2 averaged 0.34 in the first brood of snails that mated twice within 70 days indicating first mate sperm precedence. In contrast, P2 averaged 0.76 in broods of snails that remated in the following season, indicating a decreased viability of sperm from the first mate. The size of sperm-donating individuals had no effect on the fertilization success of their sperm in the first brood produced after the second copulation. Analysis of long-term sperm utilization in 23 snails that laid three to nine egg batches over 2 years revealed striking differences among individuals. Five snails (21.7%) exhibited first-mate sperm precedence throughout, eight snails (34.8%) showed second-mate sperm precedence throughout, whereas ten snails (43.5%) exhibited sperm mixing in successive batches. It is suggested that the individual variation in sperm precedence in A. arbustorum may partly be due to differences in the amount of sperm transferred. Paternity analysis in 34 batches laid by 19 wild-caught individuals of A. arbustorum indicated that at least 12 snails (63.2%) used sperm from two or more mates for the fertilization of their eggs. This suggests a high incidence of multiple paternity in broods of A. arbustorum under field conditions. 相似文献
153.
154.
Alain Dejean Céline Leroy Bruno Corbara Régis Céréghino Olivier Roux Bruno Hérault Vivien Rossi Roberto J. Guerrero Jacques H. C. Delabie Jérôme Orivel Raphaël Boulay 《Die Naturwissenschaften》2010,97(10):925-934
Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant–plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant–myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of Azteca–Cecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees’ fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree. 相似文献
155.
The evolution of bird migration—a synthesis 总被引:1,自引:1,他引:0
We approach the problem of the evolution of bird migration by asking whether migration evolves towards new breeding areas
or towards survival areas in the non-breeding season. Thus, we avoid the ambiguity of the usually discussed “southern-home-theory”
or “northern-home-theory”. We argue that migration evolved in birds that spread to seasonal habitats through gradual dispersal
to enhance survival during the non-breeding season; this in contrast to the alternative idea suggesting that migration evolved
towards new breeding areas to increase reproductive success. Our synthesis is based on the threshold model explaining how
migratory traits can change rapidly through microevolutionary processes. Our model brings former theories together and explains
how bird migration, with the appropriate direction and time program, evolves through selection after genetically non-directed
events such as dispersal and colonization. The model does not need the former untested assumptions such as competition as
a reason for migration and for the disappearance of sedentary populations or higher reproductive success in temperate breeding
areas. Our theory offers answers to questions such as how birds with a southern origin may gradually reach northern latitudes,
why migration routes may follow historical expansion routes and why birds leave an area for the non-breeding season and move
back instead of breeding on their wintering grounds. The theory proposes gradual change through selection and not sudden changes
such as long distance dispersal or mutations and can be applied to migration at all latitudes and in all directions. The scenario
provides a reasonable concept to understand most of the existing migratory phenomena on the basis of the ecology and genetics
of migratory behaviour. 相似文献
156.
Alain Dejean Bruno Corbara Frédéric Azémar James M. Carpenter 《Die Naturwissenschaften》2012,99(7):579-582
Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1?%) were captured in turn. The ant workers hunt in a group and use the “Velcro?” principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases. 相似文献
157.
Martins Dayse Carvalho da Silva Resende Iasmin Tavares da Silva Bruno José Rocha 《Environmental science and pollution research international》2022,29(28):42384-42403
Environmental Science and Pollution Research - Pesticides have been used to kill pests such as insects, fungi, rodents, and unwanted plants. Since these compounds are potentially toxic to the... 相似文献
158.
Fiore Ludovica Serranti Silvia Mazziotti Cristina Riccardi Elena Benzi Margherita Bonifazi Giuseppe 《Environmental science and pollution research international》2022,29(32):48588-48606
Environmental Science and Pollution Research - In this work, freshwater microplastic samples collected from four different stations along the Italian Po river were characterized in terms of... 相似文献
159.
da Silva Fabiano Santana Luna Carlos Bruno Barreto Siqueira Danilo Diniz da Silva Barbosa Ferreira Eduardo Araújo Edcleide Maria 《Journal of Polymers and the Environment》2022,30(3):1028-1044
Journal of Polymers and the Environment - This work aimed to investigate the biopolyethylene (BioPE)/wood powder (WP) composites compatibilized with polyethylene-grafted maleic anhydride (PE-g-MA),... 相似文献
160.