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1.
Bioassays were used to study the infectivity of cytoplasmic polyhedrosis viruses (CPVs), nuclear polyhedrosis viruses (NPVs) and entomopoxviruses (EPVs) contained in 16 nests of the paper waspPolistes hebraues F. in Réunion Island. Several virosis were propagated from 6 nest contents in 5 Lepidoptera:Catopsilia thauruma Saalmüller,Catopsilia florella F.,Callixena versicolora Mabille,Polydesma umbricola Boisduval andEagris sabadius Boisduval. Each of the previous species supported the development of one or two virosis and therefore, wasp nests must be considered as accumulating centres where infectivity of occluded entomoviruses is preserved. The accurate origin of the virosis propagated through bioassays was searched for using ecological investigations on similar natural diseases, REN analysis and a cross-transmission test onSpodoptera mauritia Boisduval. The nuclear polyhedrosis and one cytoplasmic polyhedrosis appearing in bioassays can be assigned respectively to viruses produced byC. thauruma andC. versicolora; the other virosis must be considered as developing in alternate or substitution hosts. Wasp nests could therefore be used to detect the presence of specific viruses in an environment and to collect new virus isolates. 相似文献
2.
Tubes and foraging behavior in larval Chironomidae: implications for predator avoidance 总被引:6,自引:1,他引:5
A. E. Hershey 《Oecologia》1987,73(2):236-241
Summary In laboratory experiments, I studied differential susceptibility of four co-occurring species of chironomids to a predatory damselfly. The chironomids differed in foraging behavior and could be ranked according to the amount of time they spent outside of their tubes. In choice experiments, the predator consistently selected the prey which spent more time out of the tube, and time out of tube was a significant predictor of the predation rate coefficient. Electivity indices, calculated from field samples and diet analyses of the predator, supported the laboratory results. The data suggest that exposure to predators in a heterogeneous prey community is largely determined by tubedwelling behavior. 相似文献
3.
Summary The ability of an erpobdellid leech, Erpobdella montezuma, to discriminate between two congeneric amphipod prey (Hyalella montezuma and Hyalella azteca) through mechanoreception was examined. Both E. montezuma and H. montezuma, a pelagic filter feeder, are endemic to the near thermally constant environment of Montezuma Well, Arizona, and form a highly specialized predator-prey relationship. In contrast, H. azteca, a benthic detritivore, is widely distributed throughout North America. Erpobdella montezuma was highly responsive to the prey signals of the endemic H. montezuma and showed only a limited response to H. azteca. An inverse relationship occurred between the frequency of attack and size of the leech. The abilities of Erpobdella punctata and Nephelopsis obscura, neither found in Montezuma Well, to detect the signals of both amphipod prey were also examined. These species with non-specialized diets showed a low response to the signals of both prey species. This study demonstrates that very close predator-prey relationships can develop over evolutionary time in isolated aquatic systems through the use of mechanoreception. 相似文献
4.
Paul A. Faure James H. Fullard Robert M. R. Barclay 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1990,166(6):843-849
1. | Most studies examining interactions between insectivorous bats and tympanate prey use the echolocation calls of aerially-feeding bats in their analyses. We examined the auditory responses of noctuid (Eurois astricta) and notodontid (Pheosia rimosa) moth to the echolocation call characteristics of a gleaning insectivorous bat, Myotis evotis. |
2. | While gleaning, M. Evotis used short duration (mean ± SD = 0.66 ± 0.28 ms, Table 2), high frequency, FM calls (FM sweep = 80 – 37 kHz) of relatively low intensity (77.3 + 2.9, –4.2 dB SPL). Call peak frequency was 52.2 kHz with most of the energy above 50 kHz (Fig. 1). |
3. | Echolocation was not required for prey detection or capture as calls were emitted during only 50% of hovers and 59% of attacks. When echolocation was used, bats ceased calling 324.7 (±200.4) ms before attacking (Fig. 2), probably using prey-generated sounds to locate fluttering moths. Mean call repetition rate during gleaning attacks was 21.7 (±15.5) calls/s and feeding buzzes were never recorded. |
4. | Eurois astricta and P. rimosa are typical of most tympanate moths having ears with BFs between 20 and 40 kHz (Fig. 3); apparently tuned to the echolocation calls of aerially-feeding bats. The ears of both species respond poorly to the high frequency, short duration, faint stimuli representing the echolocation calls of gleaning M. evotis (Figs. 4–6). |
5. | Our results demonstrate that tympanate moths, and potentially other nocturnal insects, are unable to detect the echolocation calls typical of gleaning bats and thus are particularly susceptible to predation. |
5.
Takayuki Ohgushi 《Population Ecology》1988,30(1):57-68
The relationships between egg predation of an herbivorous lady beetle Epilachna niponica (Lewis ) and its predator, the earwig Anechura harmandi (Burr ), were examined in both time and space. In spite of little annual, changes in egg densities, egg mortality due to predation varied considerably. There was no, clear relationship between the earwig density and the proportionate predation over the five years. The seasonal occurrence of earwig nymphs on thistle plants, however, was closely synchronized with that of egg predation. Predator attacks on the beetle occurred in a time-restricted manner. Thus, later cohorts mostly escape from heavy predatory pressure. No spatially density-depent egg predation was detected at the level of either thistle plants or thistle patches. Furthermore, there was no indication of aggregative behaviour of the earwig in response to local egg density. The earwig density was more likely to be associated with particular localities with sandy deposits available for its nest site. 相似文献
6.
Synopsis Bagrids in Bahr Shebeen Nilotic canal depend mainly on fish, insects and shrimp as well as fish embryos for food and their stomachs included runoff materials (e.g. plant foliage, glass, black crystals, coloured gravel). B. bayad maximised its efficiency of catching prey catfish by face to face attack to avoid damage by the prey's pectoral and dorsal spines. In the size classes of 10 to 30 cm standard length, B. bayad and B. docmac show diet overlap and interact with each other especially with respect to tilapias as prey. After this length, B. docmac, aided by its relatively larger mouth, shifted to larger size of tilapias to coexist with B. bayad. 相似文献
7.
Summary We used an automated technique for the observation and quantification of zooplankton swimming behavior to study the behavioral responses of two congeneric, herbivorous, freshwater copepod prey to a copepod predator (Limnocalanus macrurus). One prey, Diaptomus sicilis, often co-occurs with Limnocalanus, while previous studies indicated that the zoogeographic distribution of the second prey, Diaptomus oregonensis, was independent of the predator. We found that in the presence of Limnocalanus, D. sicilis swims more slowly and with less hopping and jumping than D. oregonensis. Diaptomus sicilis is also attacked and consumed by the predator Limnocalanus macrurus less frequently than D. oregonensis. We suggest that the faster, noisier swimming of D. oregonensis increases its vulnerability to Limnocalanus. The behavioral defenses to both prey are induced by the presence of the predator, and may represent two different anti-predator strategies, crypsis and avoidance for D. sicilis and D. oregonensis respectively. In a zoogeographical analysis D. oregonensis occurs at densities below D. sicilis in lakes where Limnocalanus is at elevated abundances, while in low-predator lakes the opposite is true. This distribution pattern supports our experimental results, and suggests that D. sicilis is adapted to survive with Limnocalanus, while D. oregonensis is not. 相似文献
8.
Synopsis Laboratory studies were conducted on 15 schools of blackchin shiners, Notropis heterodon, to determine if they altered their structure in response to changing environmental demands. The hypothesis tested was that fish schools should sacrifice a flat, hydrodynamically efficient structure in favour of an unobstructed visual field in the presence of a predator by staggering in the vertical plane. Ten schools were exposed for two weeks to a simple environment with only a current. For the next two-week period a predator was added. Five control schools were exposed to the simple environment for both two-week periods. Six of the ten treated schools increased their staggering in the vertical dimension as predicted while none of the control schools changed. This result was suggestive that hydrodynamic advantages were sacrificed. Respirometer experiments indicated these fish were capable of achieving some hydrodynamic benefits from schooling but these benefits may be a function of fish size. 相似文献
9.
Philip A. Cochran 《Environmental Biology of Fishes》1986,16(4):325-329
Synopsis Laboratory and field data suggest that several species of parasitic lampreys forage primarily at night, but data forPetromyzon marinus are equivocal. Nocturnal foraging may minimize predation risk. This may be particularly important to those species of lampreys that inhabit shallow streams. Nocturnal foraging also may enhance foraging efficiency if potential hosts at night are quiescent and more easily approached. Future experiments should be designed to avoid several potential sources of bias. 相似文献
10.
Stephen Francis Ferrari Maria Aparecida Lopes Ferrari 《Primates; journal of primatology》1990,31(3):323-338
The predator avoidance behaviour of a free-ranging group of buffy-headed marmosets,Callithrix flaviceps, was recorded in detail during the course of a long-term study of behavioural ecology at the Fazenda Montes Claros, southeastern
Brazil. Four distinct patterns of predator avoidance behaviour, each with specific vocalisations, were recognised and are
described here. The selection and use of sleeping sites by the study group are also described. An analysis of the records
indicates that these small monkeys are generally most vulnerable to predation by aerial raptors. Variations in the frequency
of alarm calls also indicate that the marmosets tend to be more vigilant at higher levels in the forest and when the leaf
cover is less extensive. The implications of group size and social structure for both the evolution and the efficacy of the
anti-predator behaviour of marmosets are also discussed. 相似文献