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1.
Summary. The major component of the trail pheromone of
the myrmicine ant Crematogaster castanea
has been identified as (R)-2-dodecanol from
the tibial glands of the hind legs. The substance gave activity comparable to the
contents of 8 tibial glands at a concentration of 1 pg per 32 cm trail. 相似文献
2.
In this paper, we used the food-correlated search behavior observed in foraging ants returning to a previously rewarding site to study information transfer during recruitment in the ant Lasius niger. We hypothesized that, if information about the characteristics of the food is conveyed during recruitment, food-correlated search tactics should also be observed in recruited workers. Our results show that the characteristics of the trajectories of recruited workers are comparable to those of scout ants returning to a site or prior food find and depend more on the type (prey/sugar) than on the quality (sugar concentration) of the food discovered by the scouts. Independent of sugar concentration, workers recruited to a source of sugar search with a greater sinuosity than workers recruited to a prey. Experimental manipulation of the recruitment signals (chemical trail and contact between ants) shows that the trail pheromone laid down by recruiting ants does not play a role in the modification of trajectory sinuosity. This change appears to be most likely triggered by a direct perception of the residue of sugar smeared on the body of the recruiting workers coming back to the nest.Communicated by J. Heinze 相似文献
3.
Summary. In earlier investigations on host plant discrimination of leaf beetles glucosinolates were described as feeding stimulants
for the Brassicaceae specialist Phaedon cochleariae F. (Coleoptera: Chrysomelidae). However, since these findings could not be confirmed in later studies offering 2-propenylglucosinolate
in concentrations corresponding to those detected in host plant leaf material, the identification of feeding stimulants of
this leaf beetle species remained unclear. In order to investigate which compounds of the host plant Sinapis alba (Brassicaceae) are involved in feeding stimulation, leaf extracts of different polarities were tested in bioassays with adults
of P. cochleariae. Number of feeding beetles and net consumption rates were highest on pea leaves painted with methanol extracts of S. alba, whereas weak feeding responses were also detectable for hexane extracts. In subsequent bioassay-guided fractionations of
methanol extracts with semi-preparative high performance liquid chromatography, two distinct fractions, one containing glucosinolates
and another containing flavonoids, were found to stimulate beetles to feed to variable degrees. Other collected fractions
had zero activity. The combination of both active fractions evoked significantly higher consumption rates and stimulated more
beetles to feed than fractions tested individually. At least one compound of each fraction, among these the main glucosinolate
of S. alba, 4-hydroxybenzylglucosinolate, act additively. Effects of two different naturally-occurring ratios of glucosinolates and
flavonoids on the strength of feeding responses were investigated by use of extracts of two sets of host plants differently
exposed to radiation. One set was outdoors-exposed, whereas the second set was kept in the greenhouse. However, the feeding
behaviour of P. cochleariae was not affected by the significantly different relative compositions of both compound classes in the host material. In conclusion,
mustard leaf beetles need a combination of distinct plant metabolites acting in concert for feeding stimulation, whereby the
mere presence of these stimulants, but probably not the ratio of involved compounds, determines their feeding response. 相似文献
4.
In bumblebees all species of the subgenus Psithyrus are social parasites in the nests of their Bombus hosts. In the bumblebee B. terrestris we investigated how colony size influences survival rates of nest entering females of the social parasite Psithyrus vestalis. Furthermore, we studied whether the host worker’s dominance status and age are reflected in its individual scent and whether
Psithyrus females use volatiles to selectively kill host workers. The survival rate of Psithyrus vestalis females drops from 100%, when entering colonies with five workers, to 0% for colonies containing 50 host workers. Older host
workers, born before the nest invasion, were selectively killed when Psithyrus females entered the nest. In contrast, all workers born after the nest invasion survived. The host workers’ dominance status
and age are reflected by their individual odours: newly emerged workers produced a significantly lower total amount of secretions
than 4-day-old workers. In chemical analyses of female groups we identified saturated and unsaturated hydrocarbons, aldehydes,
and unsaturated wax-type esters of fatty acids. In a discriminant function analysis different worker groups were mainly separated
by their bouquets of hydrocarbons. Killed workers release significantly more scent and of a different chemical composition,
than survivors. Survivors alter scent production and increase it beyond the level of the killed workers within 1 day of the
invasion. The Psithyrus female clearly maintains reproductive dominance utilizing these differences in the odour bouquets as criteria for killing
workers that compete for reproduction. 相似文献
5.
Beata Szafranek Elżbieta Synak Danuta Waligóra Janusz Szafranek Jan Nawrot 《Chemoecology》2008,18(4):205-216
Summary. The sampling behavior of the Colorado potato beetle Leptinotarsa decemlineata Say (CPB) involves examination of the surface
of potato leaves. It has been suggested that leaf surface compounds (volatiles and cuticular waxes) may be involved in host-plant
recognition, acceptance or discrimination. Here we report on the effect of leaf surface extracts of six Polish commercial
potato varieties on CPB feeding. We tested the influence of potato leaf surface extracts on CPB adult and larval feeding,
then separated the extracts with HPLC, and finally tested the effect of the HPLC-separated fractions on CPB feeding. The bioassays
were performed using potato leaf discs deprived of their original surface compounds. Applied to test discs at concentrations
ten times higher than natural (10 leaf area equivalent), the extracts deterred CPB adults and larvae from feeding. HPLC-separated
fractions composed of alkanes, sesquiterpene hydrocarbons, wax esters, benzoic acid esters, fatty acid methyl, ethyl, isopropyl
and phenylethyl esters, aldehydes, ketones, methyl ketones, fatty acids, primary alcohols, β-amyrin and sterols did not affect
adult CPB feeding. Similarly, alkanes, sesquiterpene hydrocarbons, wax esters, methyl ketones, sesquiterpene alcohols and
secondary alcohols had no effect on larval CPB feeding. The sterol fraction (cholesterol, β-sitosterol and stigmasterol) acted
as a phagostimulant to CPB larvae. We isolated a fraction demonstrating a phagodeterrent effect on CPB adults and larvae.
The qualitative composition of the deterrent fraction was quite similar in all potato extracts, but there were quantitative
differences between the varieties. Much further work is needed to identify the compounds that can produce the deterrent effect. 相似文献
6.
The aim of this study was to examine the effects of chemical nonylphenols (NPs) on the antioxidant system of Microcystis aeruginosa strains. The degradation and sorption of NPs by M. aeruginosa were also evaluated. High concentrations of NPs (1 and 2 mg/l) were found to cause increases in superoxidase dismutase (SOD)
and glutathione-S-transferase (GST) activities and in glutathione (GSH) levels. These results suggest that toxic stress manifested by elevated
SOD and GST levels and GSH contents may be responsible for the toxicity of NPs to M. aeruginosa and that the algal cells could improve their antioxidant and detoxification ability through the enhancement of enzymatic
and nonenzymatic prevention substances. The observed elevations in GSH levels and GST activities were relatively higher than
those in SOD activities, indicating that GSH and GST contributed more in eliminating toxic effects than SOD. Low concentrations
of NPs (0.05–0.2 mg/l) enhanced cell growth and decreased GST activity in algal cells of M. aeruginosa, suggesting that NPs may have acted as a protecting factor, such as an antioxidant. The larger portion of the NPs (>60%)
disappeared after 12 days of incubation, indicating the strong ability of M. aeruginosa to degrade the moderate persistent NP compounds. The sorption ratio of M. aeruginosa after a 12-day exposure to low nominal concentrations of NPs (0.02–0.5 mg/l) was relatively high (>30%). The fact that M. aeruginosa effectively resisted the toxic effects of NPs and strongly degraded these pollutants indicate that M. aeruginosa cells have a strong ability to adapt to variations in environmental conditions and that low and moderate concentrations of
organic compounds may favor its survival. Further studies are needed to provide detailed information on the fate of persistent
organic pollutants and the survival of algae and to determine the possible role of organic pollutants in the occurrence of
water blooms in eutrophic lakes. 相似文献
7.
Summary. Although terrestrial turtles have served as a model for studies of olfactory neurophysiology, little is known about how they
use chemical information in an ecological sense. We tested whether box turtles (Terrapene carolina) use chemical information to distinguish between predatory and nonpredatory mammals. Box turtles in our study exhibited more
escape behavior when exposed to urine from a predator (coyote, Canis latrans) than when exposed to urine from a nonpredator (white-tailed deer, Odocoileus virginianus) or a blank control. Escape behavior is consistent with an antipredator response. In addition, the turtles decreased their
handling time for food when in the presence of urine from either species of mammal in comparison to the blank, indicating
that chemical cues from mammals in general may result in increased vigilance by terrestrial turtles. Examination of a variety
of response variables may be important for adequate assessment of the ecological role of chemosensory behavior. 相似文献
8.
Division of labor is a key factor in the ecological success of social groups. Recent work suggests that division of labor can emerge even without specific adaptations for task specialization and that it can appear in incipient social groups as a self-organizational property. We investigated experimentally how selection and self-organization may interact during the evolution of division of labor by examining task performance in groups of normally solitary versus normally social ant queens. We created social pairs of colony-founding queens from two populations of the ant Pogonomyrmex californicus, one in which queens are normally solitary and one in which queens form foundress groups, and observed their behavior during nest excavation. In both populations, one of the two queens usually performed most of the excavation, becoming the excavation specialist. We could predict which queen would become the specialist based on their relative propensities to perform the task in other contexts, consistent with a variance-based model of task specialization. The occurrence of specialization even when group members were not adapted to social life suggests that division of labor may well have been present in incipient queen groups. However, division of labor can result in cost skew among group members, and thus, paradoxically, within-group selection may constrain or even reduce specialization. Consistent with this effect, pairs of normally solitary queens were significantly more asymmetrical in their task performance than normally social pairs, in which both queens nearly always performed the behavior to some degree.Communicated by J. Heinze 相似文献
9.
Summary. Females of both species start their pheromone-releasing activity on the second day after emergence at the beginning of the
photophase. During the present work, a peak of calling activity with close to 100% of active Ph. nigrescentella females was registered 1.5 hour after the light had been put on. The high pheromone release behaviour with 50% active females
lasted for 3 hours. The calling activity of the group of females was about 6 h/day. The beginning of a photophase under laboratory
conditions or an early morning in nature is a common period for sex pheromone release in the genus Phyllonorycter. (8Z,10E)-tetradecadien-1-yl acetate (8Z,10E-14:Ac), (8Z,10E)-tetradecadien-1-ol (8Z,10E-14:OH) and (8E,10Z)-tetradecadien-1-yl acetate (8E,10Z-14:Ac) in the ratio 96:4:traces as well as 8Z,10E-14:Ac and 8Z,10E-14:OH in the ratio 88:12 collected by Solid Phase Micro Extraction (SPME) were found to be specific for the calling periods
of virgin Phyllonorycter insignitella and Ph. nigrescentella females respectively. Field trapping experiments demonstrated that all three compounds are important for the attraction of
Ph. insignitella males while only 8Z,10E-14:Ac is the essential sex pheromone component for Ph. nigrescentella. The pheromone activity of all three compounds is reported for the first time. Addition of either 8Z,10E-14:OH or 8E,10Z-14:Ac to 8Z,10E-14:Ac did not have a significant effect on the attraction of Ph. nigrescentella males, while the efficiency of the three component blend was 5 times lower as compared to that of 8Z,10E-14:Ac. Our data demonstrate that 8Z,10E-14:OH and 8E,10Z-14:Ac play a dual function, they are minor sex pheromone components of Ph. insignitella essential for attraction of conspecific males and show an allelochemical, antagonistic effect on Ph. nigrescentella males and, thus, ensuring specificity of the mate location signal in two related Phyllonorycter species. 相似文献
10.
Summary. Myrmecophytic plants use obligate ant mutualists as a constitutive
indirect defence mechanism. These plants often produce cellular food bodies (FBs) to
nourish their resident ants. Lipids, proteins, and even highly specialised compounds
such as glycogen have been reported from FBs, but detailed chemical analyses of FB
composition have so far been presented only for Southeast Asian Macaranga
and Central American Piper myrmecophytes. Here we
report the chemical composition of FBs of five myrmecophytic Acacia
(Fabaceae) species from Mexico using HPLC (carbohydrates and proteins) and GC-MS
(lipids). Feeding experiments revealed no hints on any use of external food sources
by the inhabiting Pseudomyrmex ants. These ants
obviously rely completely on FBs and extrafloral nectar provided by their hosts.
The total content of nutrients in Acacia FBs was 15-25% of FB
dry mass, being much lower than in Macaranga or
Piper FBs. Proteins were dominating (8-14 % dm)
in Acacia FBs and thus were present in higher amounts than in
Macaranga FBs, yet in lower amounts than in
Piper. Lipids contributed 1-9 %
of dry mass, showing a lower proportion than in FBs of Macaranga
or Piper. Carbohydrates made up 3-11 % dm, reaching
in most Acacia species the same range as observed in
Macaranga and in Piper FBs.
Water content was 18-24 % of FB fresh mass, and structural tissue obviously made up
a much higher proportion in Acacia FBs than in
Macaranga or Piper
FBs. Both characters might represent an adaptation to producing FBs unprotected at
the leaf tips under dry conditions. Acacia FBs
contain all amino acids and all fatty acids that are considered essential for
insects, and their contents of lipids and proteins are higher than in the leaves
from which they are ontogenetically derived. This indicates a putatively adaptive
enrichment of nutritionally valuable compounds in structures functioning as ant-food. 相似文献
11.
Innate antipredator responses of Arctic charr (<Emphasis Type="Italic">Salvelinus alpinus</Emphasis>) depend on predator species and their diet 总被引:2,自引:0,他引:2
The ability to discriminate between more dangerous and less dangerous predators can have serious fitness advantages for fish juveniles. This is especially true for hatchery-reared fish young used for stocking, because their post-release mortality is often much higher than that of wild-born conspecifics. We tested whether two coexisting fish predators and their different diets induce innate behavioral responses in predator-naive Arctic charr (Salvelinus alpinus) young originating from an endangered hatchery-bred population used for re-introductions. We predicted the antipredator responses of charr to be stronger towards chemical cues of brown trout (Salmo trutta) and pikeperch (Stizostedion lucioperca) than towards odorless control water. More pronounced antipredator behavior was predicted in treatments with predators fed on charr than when their diet consisted of another sympatric salmonid, European grayling (Thymallus thymallus), or when they were food-deprived. The Arctic charr young showed strong antipredator responses in all brown trout treatments, whereas odors of the less likely predator pikeperch were avoided with conspecific diet only. Freezing was the most sensitive antipredator behavior, as it was completely absent in control treatments. We found considerable individual variation in the amount and strength of antipredator responses. Although almost half of the charr failed to show antipredator behavior towards the piscivores, those with the innate ability showed highly sensitive recognition of predator odors. Our results indicate that the innate antipredator behavior of the juvenile fish is already finely tuned to respond specifically to chemical cues from different fish predators and even their diets.Communicated by J. Krause 相似文献
12.
Maud C. O. Ferrari François Messier Douglas P. Chivers 《Behavioral ecology and sociobiology》2008,62(7):1079-1083
A prerequisite for prey to show adaptive behavioural responses to predators is that the prey has the ability to recognise
predators as threats. While predator recognition can be innate in many situations, learning is often essential. For many aquatic
species, one common way to learn about predators is through the pairing of a novel predator odour with alarm cues released
from injured conspecifics. One study with fish demonstrated that this mode of learning not only allows the prey to recognise
the predatory cues as a threat, but also mediates the level of threat associated with the predator cues (i.e. threat-sensitive
learning). When the prey is exposed to the novel predator with a high concentration of alarm cues, they subsequently show
a high intensity of antipredator response to the predator cues alone. When exposed to the predator with a low concentration
of alarm cues, they subsequently show a low-intensity response to the predator cues. Here, we investigated whether larval
mosquitoes Culex restuans have the ability to learn to recognise salamanders as a threat through a single pairing of alarm cues and salamander odour
and also whether they would learn to respond to salamander cues in a threat-sensitive manner. We conditioned individual mosquitoes
with water or a low, medium or high concentration of crushed conspecific cues (alarm cues) paired with salamander odour. Mosquitoes
exposed to salamander odour paired with alarm cues and subsequently exposed to salamander odour alone responded to the salamander
as a threat. Moreover, the intensity of antipredator response displayed during the conditioning phase matched the response
intensity during the testing phase. This is the first demonstration of threat-sensitive learning in an aquatic invertebrate. 相似文献
13.
We examine vigilance within a mixed-species troop of saddleback (Saguinus fuscicollis) and moustached (S. mystax) tamarins over a complete year. Saddleback tamarins were consistently more vigilant than moustached tamarins. This may be linked to their preference for lower strata. In accordance with previous studies of other primates, vigilant tamarins of both species were significantly further away from their nearest neighbours, and were also at lower heights in the forest than non-vigilant individuals. There was no observed sex difference in the amount of time spent vigilant. In terms of modes of scanning, the saddleback tamarins looked up significantly more frequently than the moustached tamarins, whereas there was no difference between the species in the frequency of side sweeps. There were no differences between the sexes in the frequencies of either type of vigilant behaviour. The proportion of time spent vigilant was higher than average immediately prior to entering a sleeping site for saddleback tamarins, but not for moustached tamarins. Both species were more vigilant immediately after exiting a sleeping site than at other times of the day. There was significant variation in the amount of time devoted to vigilance over the course of the year. These findings are discussed with respect to the social structure, ecology and main predator threats facing these species.Communicated by D. Watts 相似文献
14.
Deborah A. Hutchinson Alan H. Savitzky Akira Mori Jerrold Meinwald Frank C. Schroeder 《Chemoecology》2008,18(3):181-190
Summary.
Rhabdophis tigrinus obtains defensive steroids (bufadienolides) from its diet and sequesters those compounds in specialized structures on its
neck known as nuchal glands. Hatchling snakes lacking these steroids must acquire them from toads consumed as prey. Here we
show that females provision bufadienolides to their offspring in amounts correlated to the quantity in their own nuchal glands;
thus, chemically protected mothers produce defended offspring. Bufadienolides can be provisioned to embryos via deposition
in yolk and by transfer across the egg membranes within the oviducts. Maternally provisioned bufadienolides persist in the
nuchal glands of juvenile snakes from the time of hatching in late summer until the following spring, when toads of ingestible
size become abundant. Therefore, maternal provisioning may provide chemical protection from predators for young R. tigrinus in the absence of dietary sources of bufadienolides. 相似文献
15.
16.
Summary. The harvestman Mitopus morio (Phalangidae) is
a generalist predator. It is known to prey on larvae of the
chrysomelid leaf beetle Oreina cacaliae defended by plant
acquired pyrrolizidine alkaloids (PAs). Tracer feeding
experiments were performed to determine how harvestmen
tolerate protoxic PAs. Minced meat containing either
[14C]senecionine or [14C]senecionine N-oxide was fed to
M. morio and subsequently feces and bodies were analyzed.
Labeled alkaloid N-oxide remained stable and was eliminated
almost unaltered with the feces; only 10% was recovered
as tertiary PA. In contrast, approximately 80% of
labeled tertiary alkaloid (senecionine) ingested with the diet
was N-oxidized and eliminated; the remaining 20% consisted
of unchanged senecionine and a polar metabolite
of unknown structure. Harvestmen process their diet by
excreting digestive juice, indicated by bleaching of the meat
color. Analysis of the processed diet revealed some N-oxidation
of [14C]senecionine, suggesting the gut as the site of Noxidation.
Analysis of the bodies of harvestmen 80 hours
after the tracer feeding pulse revealed only trace amounts of
the polar metabolite. Neither senecionine nor its N-oxide
could be detected in the body extracts. The results are discussed
in relation to the strategies of PA adapted insects to
avoid accumulation of tertiary PAs in living tissues. 相似文献
17.
Frogs and toads commonly form large choruses around suitable breeding habitat during the mating season. Although often regarded
as a constraint on the acoustic behavior of signalers and receivers, the sounds of a chorus could also serve as an acoustic
beacon that allows some frogs to locate the breeding aggregation. Attraction to chorus sounds might be particularly important
for explosively breeding frogs. In these species, which often mate just one or a few days during the year, the timing and
location of breeding aggregations can be unpredictable because their formation often depends on local climatic factors, such
as rainfall or a change in temperature. I used laboratory playback experiments to test the hypothesis that male wood frogs
(Rana sylvatica), an explosively breeding frog, exhibit positive phonotaxis toward the sound of a conspecific chorus. Males were released
at the center of a rectangular arena with a speaker positioned in each corner facing toward the release point. In a single-stimulus
experiment, more males approached a speaker broadcasting a conspecific chorus than the three silent speakers in the arena.
In a two-stimulus experiment, more males approached a speaker broadcasting a conspecific chorus compared to the two silent
speakers or a fourth speaker simultaneously broadcasting the spectrally overlapping sound of a heterospecific (R. septentrionalis) chorus. These results are consistent with the hypothesis that male wood frogs could use the sound of a chorus as a beacon
to locate a short-lived breeding aggregation. 相似文献
18.
Matthias Bandilla Teija Hakalahti-Sirén E. Tellervo Valtonen 《Behavioral ecology and sociobiology》2008,62(6):975-982
Mating is essential for sexually reproducing species to pass on their genes. For sexual parasites, this implies a need to
switch the host in the search for a mate when potential partners are not available on the same host, although host switching
includes risks like starvation and predation. Studies of mate-searching behavior predict that commonly only one sex searches
for mating partners while the other remains stationary. In the present work, we experimentally infected rainbow trout (Oncorhynchus mykiss) with the fish ectoparasite Argulus coregoni and determined whether the sex, age and the presence of mating partners influenced the host switching activity. Our results
show that increased host switching by A. coregoni occurred only after the parasite reached the adult stage and a difference between the sexes was also recorded. Host switching
by mature males was enhanced when no mating partners were present on the same host, whereas females remained mainly stationary
on their host regardless of male presence or absence. Our data therefore support the hypothesis that there is a strategic
difference in reproductive behavior between males and females; males invest energy in mate searching while females are rather
stationary and invest into body size and hence increased fecundity. Our data also showed that leaving the host to find a mate
is potentially costly in terms of predation since a substantial number of free-swimming parasites were eaten by fish. 相似文献
19.
Behavioural variation is known to occur between individuals of the same population competing for resources. Individuals also vary with respect to their boldness or shyness. An individuals position along the shy-bold axis may be defined as the extent to which it is willing to trade off potentially increased predation risks for possible gains in resources. Similarly, group living may be interpreted as a trade-off between anti-predatory tactics and foraging efficiency. The responses of three-spined sticklebacks (Gasterosteus aculeatus) were tested across four social contexts to assess relative boldness or shyness and to further examine whether their behaviour would be consistent within and between contexts. Individuals displayed consistent responses within and between the first two contexts: those individuals which resumed foraging rapidly after a simulated aerial predator attack also displayed low shoaling tendencies. Such fish were deemed to be bold, whilst those which displayed the converse behaviour, slow resumption of foraging and a high shoaling tendency, were deemed to be shy. In a third context, bold individuals out-competed shy conspecifics for food. Boldness was also positively correlated with growth over a 6-week period. The position adopted by an individual within a group is usually interpreted as a trade-off between predation risk and foraging efficiency—both are greater at the front of a mobile group. Bold individuals showed significantly stronger tendencies towards front positions than shy conspecifics. The results suggest that, contrary to some previous studies on other animals, bold or shy behaviour in sticklebacks is consistent between contexts.Communicated by T. Czeschlik 相似文献
20.
Both theoretical and empirical work has shown that group size increases with increasing ecological constraints on solitary breeding. Ecological constraints refer to extrinsic factors such as availability of breeding sites, food or mates. Common eider (Somateria mollissima) females pool their broods and share brood-rearing duties, or rear broods alone. Females are often in poor condition at hatching, as incubation is accomplished without feeding, and variation in body condition is largely environmentally induced and thus unpredictable. We found that the intensity of and duration of parental care that females provide is positively correlated with their body condition at hatching. This suggests that body condition is an ecological constraint on successful solitary breeding. We further observed that group productivity in common eider broods is a decelerating function of the number of tending females. As predicted, females in poorer condition (i.e., facing stronger ecological constraints) were found in larger groups. This result is straightforward if solitary tenders can enter any group at no cost. However, if entry is group-controlled, stable groups of non-relatives are predicted not to occur when per capita reproduction declines with group size. The N-person staying incentive model permits groups to form under these conditions, because reproduction is unevenly divided between dominants and subordinates in the group. We discuss the plausibility of these alternative models of group size for understanding the grouping behavior of brood-caring female common eiders.Communicated by M. Webster 相似文献