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581.
Social animals often use vocal communication signals that contain individual signatures. As bats emit echolocation calls several
times per second to orient in space, these might seem ideal candidates for conveying the caller's individual identity as a
free by-product. From a proximate perspective, however, coding of caller identity is hampered by the simple acoustic structure
of echolocation signals, by their task-specific design and by propagation loss. We investigated the occurrence of individual
signatures in echolocation calls in individually marked, free-living Bechstein's bats (Myotis bechsteinii) in a situation with defined social context in the field. The bats belonged to two different colonies, for both of which
genetic data on relatedness structure was available. While our data clearly demonstrate situation specificity of call structure,
the evidence for individual-specific signatures was relatively weak. We could not identify a robust and simple parameter that
would convey the caller's identity despite the situation-specific call variability. Discriminant function analysis assigned
calls to call sequences with good performance, but worsened drastically when tested with other sequences from the same bats.
Therefore, we caution against concluding from a satisfactory discrimination performance with identical training and test sequences
that individual bats can reliably be told apart by echolocation calls. At least the information contained in a single call
sequence seems not to be sufficient for that purpose. Starting frequencies did give the best discrimination between individuals,
and it was also this parameter that was correlated with genetic relatedness in one of our two study colonies. Echolocation
calls could serve as an additional source of information for individual recognition in Bechstein's bats societies, while it
is unlikely that a large number of individuals could be reliably identified in different situations based on echolocation
alone. 相似文献
582.
Allozyme electrophoresis was conducted in an attempt to identify the origin ofMarenzelleria sp. found in the North Sea and Baltic Sea. The analysis covered eight enzymes with ten loti from nine populations found on the North American Atlantic toast, these populations in the North Sea and five populations in the Baltic. The North Sea spionids correspond to the Type IMarenzelleria from North American coastal waters between Barnstable Harbor (Massachusetts) and Cape Henlopen (Delaware). Nei's genetic distance between these North American populations and those from the North Sea wasD = 0.010 to 0.020. TheMarenzelleria sp. found in the Baltic Sea very probably stems from North American populations of Type II found from the region of Chesapeake Bay (Trippe Bay) south to the Currituck Sound (North Carolina). The genetic distance between these North American populations and the Baltic populations isD = 0.000 to 0.001. The invaders appear to have lost little of their genetic variation while colonizing the North and Baltic Seas. Probably, both colonizing events tan be attributed to large numbers of individuals reaching Europe simultaneously on one or more occasions. In addition, aMarenzelleria Type III was found by electrophoresis among specimens from Currituck Sound (North Carolina), rohere it is sympatric withMarenzelleria Type II. Salinity is discussed as an important factor for the establishment ofMarenzelleria Type I in the North Sea and Type II in the Baltic Sea. 相似文献
583.
Malia Chevolot Peter H. J. Wolfs Jónbjörn Pálsson Adriaan D. Rijnsdorp Wytze T. Stam Jeanine L. Olsen 《Marine Biology》2007,151(4):1275-1286
Population genetic structure of the thorny skate (Amblyraja radiata) was surveyed in >300 individuals sampled from Newfoundland, Iceland, Norway, the Kattegat and the central North Sea. A 290-bp
fragment of the mt cytochrome-b gene was first screened by SSCP. Sequences of SSCP haplotypes revealed 34 haplotypes, 14 of
which were unique to Iceland, 3 to Newfoundland, 1 to Norway and 3 to the Kattegat. The global F
ST was weak but significant. Removal of the two Kattegat locations, which were the most differentiated, resulted in no significant
genetic differentiation. Haplotype diversity was high and evenly distributed across the entire Atlantic (h = 0.8) with the exception of the North Sea (h = 0.48). Statistical parsimony revealed a star-like genealogy with a central widespread haplotype. A subsequent nested clade
analysis led to the inference of contiguous expansion with evidence for long distance dispersal between Newfoundland and Iceland.
Historical demographic analysis showed that thorny skates have undergone exponential population expansion that started between
1.1 million and 690,000 years ago; and that the Last Glacial Maximum apparently had little effect. These results strongly
differ from those of a parallel study of the thornback ray (Raja clavata) in which clear structure and former refugial areas could be identified. Although both species have similar life history
traits and overlapping ranges, the continental shelf edge apparently does not present a barrier to migration in A. radiata, as it does for R. clavata. 相似文献
584.
Summary. The pollen beetle, Meligethes aeneus, is an important pest of oilseed rape, Brassica napus. Larvae of this species feed only in the buds and flowers of Brassicaceae. One important natural enemy of this beetle is
the parasitoid Phradis morionellus that attacks larvae in buds and flowers and also feeds on the flowers. The preferences for odours of non-infested and infested
rape were tested for both starved and fed parasitoids in Y-tube olfactometer experiments. The volatile blend released from
pollen beetle-infested and non-infested flowering rape and from pollen beetle larvae was identified and quantified. Gas chromatography-electroantennodetection
analyses were performed with female P. morionellus. Parasitoids in both treatment groups preferred infested rape, but the proportion of responding female P. morionellus was significantly lower for the group that was starved. Six of the 20 volatiles identified were released at higher rates
from infested rape than from non-infested. None of these compounds was found in pollen beetle larvae headspace. P. morionellus antennae detected both major and minor components in the volatile blend. The volatiles released at a significantly higher
rate from infested rape and detected by P. morionellus antennae were (Z)-3-hexenylacetate, (Z)-3-hexenol, 3-butenyl isothiocyanate and (E,E)-α-farnesene. 相似文献
585.
586.
Chemical-mediated effects of predatory fish on chironomid larvae behaviour have been ignored so far. Sediment-dwelling chironomid larvae inhabit protective burrows from which they extend their bodies only to feed on deposited detritus and microalgae from the surrounding sediment. Here, we performed factorial laboratory experiments to study whether fish-borne chemical cues (kairomones) are responsible for behavioural trait changes of chironomid larvae, and whether chironomid larvae are able to assess the densities of fish predators and food resources and the trade-off between them. We exposed naïve Chironomus riparius larvae to the chemical presence of zero, one, and ten predator fish (Rutilus rutilus) and offered two resource levels (low food, high food) for each treatment. Kairomones induced significant inherent behavioural trait changes in chironomid larvae. During the first 120 min after exposing chironomids to fish-conditioned water, we found a significant increase in digging activity with increasing predator density. After 3 days of exposure, the deepest chironomid burrows were found in treatments with the highest predator density. Chironomid larvae were significantly able to adjust their foraging behaviour to different predator densities and food concentrations and trade off between them; that is, when fish predators were more abundant or when more food resources were available, the foraging activities of larvae were significantly reduced. Our data suggest that chemically mediated trait changes (burrowing and foraging behaviour) may cascade through the littoral food web. 相似文献
587.
Nathália Nascimento Thales A. P. West Lisa Biber-Freudenberger Eráclito R. de Sousa-Neto Jean Ometto Jan Börner 《Journal of Land Use Science》2020,15(2-3):127-141
ABSTRACT Deforestation driven by agricultural expansion is a major threat to the biodiversity of the Amazon Basin. Modelling how deforestation responds to environmental policy implementation has thus become a policy relevant scientific undertaking. However, empirical parameterization of land-use/cover change (LUCC) models is challenging due to the high complexity and uncertainty of land-use decisions. Bayesian Network (BN) modelling provides an effective framework to integrate various data sources including expert knowledge. In this study, we integrate remote sensing products with data from farm-household surveys and a decision game to model LUCC at the BR-163, in Brazil. Our ‘business as usual’ scenario indicates cumulative forest cover loss in the study region of 8,000 km2 between 2014 and 2030, whereas ‘intensified law-enforcement’ would reduce cumulative deforestation to 1,600 km2 over the same time interval. Our findings underline the importance of conservation law enforcement in modulating the impact of agricultural market incentives on land cover change. 相似文献
588.
Recent theory and empirical work suggests that there may be variation among females in mate preferences that is adaptive.
One of the possible mechanisms maintaining variability in preferences and preferred traits is that the benefits of mate choice
may depend on compatibility with potential mating partners. We examined fitness consequences of mate choice in a species of
fish, the sand goby, Pomatoschistus minutus with a special focus on mate compatibility. Females were given the opportunity to establish their mate preferences in a dichotomous
mate choice experiment. This information was then applied by mating the focal or control female with either the preferred
or the non-preferred male. The parental performance of the males of these four mating combinations was then measured. In a
separate experiment, we assessed the female differential allocation by determining the residual gonad weight of spawned females
as a measure of the proportion of eggs spawned. We also estimated the amount of filial cannibalism separately for both sexes.
Our results show that preferred males provided benefits in the form of an increased number of hatching eggs. This benefit
was the same when the male was mated with a focal or a control female. Hence, we found no support for benefits that depend
on mate compatibility. Neither did we find support for the hypothesis that females would lay a different number of eggs depending
on the male status. The results also indicate that male filial cannibalism has a strong role in determining hatching success
in this species. 相似文献
589.
Summary. Male satin moths, Leucoma (Stilpnotia) salicis L. (Lepidoptera, Lymantriidae) were attracted only to (3Z,6R,7S,9R,10S)-isomer out of the four (3Z)-cis-6,7-cis-9,10-diepoxy-3-henicosenes (leucomalure). This was demonstrated by field trapping test with a bivoltine population in a mixed poplar-willow forest along the flood area of the river Danube at Adony, Hungary. 相似文献
590.
Joris M. Koene Tina Pförtner Nico K. Michiels 《Behavioral ecology and sociobiology》2005,59(2):243-249
Sexual conflict between mating partners can give rise to strategies that are advantageous for one sex but harmful to the opposite sex. Usually, sperm donors develop (offensive) traits to enhance their chances in sperm competition, while sperm recipients evolve (defensive) traits that allow them to stay in control of who fathers their offspring. Here, we demonstrate that these processes are also at work in simultaneous hermaphrodites. The hermaphroditic earthworm Lumbricus terrestris uses 40 to 44 copulatory setae to pierce into its partner's skin, causing damage and injecting a substance from its setal glands. Experimental injection of the gland substance indicates that a refractory period may be induced. More importantly, removal of the copulatory setae shows that they influence the partner's sperm uptake. When the setae are present, more sperm are taken up and sperm are distributed more equally over the four spermathecae. We interpret this as a strategy that stacks the odds for the donor's sperm in fertilizing cocoons. 相似文献