Search results for "Predation"
showing 10 items of 589 documents
Adapting a Phage to Combat Phage Resistance
2020
Phage therapy is becoming a widely recognized alternative for fighting pathogenic bacteria due to increasing antibiotic resistance problems. However, one of the common concerns related to the use of phages is the evolution of bacterial resistance against the phages, putatively disabling the treatment. Experimental adaptation of the phage (phage training) to infect a resistant host has been used to combat this problem. Yet, there is very little information on the trade-offs of phage infectivity and host range. Here we co-cultured a myophage FCV-1 with its host, the fish pathogen Flavobacterium columnare, in lake water and monitored the interaction for a one-month period. Phage resistance was…
Infanticide in the evolution of reproductive synchrony: effects on reproductive success.
2007
Synchronous breeding in animals and plants has stimulated both a theoretical and empirical examination of the possible benefits of active synchronization. The selective pressures of predation and infanticide are the strongest candidates proposed to explain the evolution of reproductive synchrony. Alternatively, breeding asynchronously with conspecifics may ensure a greater availability of resources per breeder. However, the possible fitness benefits resulting from active asynchronization have not yet received attention in evolutionary ecology. Here we present a hypothesis, based on a graphical model, illustrating the costs and benefits of the two modes of reproduction. We tested the hypothe…
Direction and strength of selection by predators for the color of the aposematic wood tiger moth
2011
Conventionally, predation is assumed to select for conspicuousness and uniformity of warning signals in aposematic (i.e., chemically defended and warning signaling) prey because this enhances predators' initial and learned avoidance. On the other hand, it has been suggested that both variation in the background where the signal is displayed as well as variation in predators' probability to attack defended prey may favor intermediate signals or relax selection for signal monomorphism. We studied the direction and strength of selection for the hind wing color (orange vs. red) of female Parasemia plantaginis moths. Birds found the moths aversive and avoided them by sight both in laboratory and…
Helminth infestation of three fishes (Serranus scriba, Mullus surmuletus, Scorpaena porcus)from a coastal seaground in the Gulf of Palermo (Tyrrhenia…
1997
Abstract The results of a year's survey on the parasitic infestation of the gastrointestinal tract of three species of benthic fish, namely Serranus scriba, Mullus surmuletus, and Scorpaena porcus, living in a restricted coastal seaground in the N/W sector of the Gulf of Palermo, are reported and critically discussed. Fish populations were sampled monthly by means of a trammel net, according to the local fishing usage. As many as nine helminth species, five of them trematodes and four nematodes, were collected from the gastrointestinal tract of 625 individuals. Infestation was most intense in M. surmuletus, with a peak in the spring. S. scriba was especially parasitized during the spring an…
How Did the Cuckoo Get Its Polymorphic Plumage?
2012
One hundred and fifty years ago, the English naturalist Henry Walter Bates first developed the theory of mimicry ( 1 ). Based on his field observations in the Amazon, he argued that the uncanny likeness of unrelated butterflies is an evolutionary adaptation whereby edible butterflies avoid predation by imitating the coloration of venomous butterfly species without paying the cost of arming themselves. Such “Batesian mimicry” is a dynamic parasitic game between three players, in which a harmless species (the mimic) escapes predation by imitating the warning signals of harmful species (the model) that a shared predator (the dupe) has learned to avoid. On page 578 of this issue, Thorogood and …
Attraction of kestrels to vole scent marks visible in ultraviolet light
1995
IN northern Europe, broad four-year oscillations in small rodent and raptor populations are synchronous over hundreds of square kilometers1–6. Crashes in vole populations can induce wide emigration (> 1,000 km) of their predators7 –9, but almost nothing is known about how predators rapidly detect areas of vole abundance. Here we report on laboratory and field experiments on voles (Microtus agrestis) and kestrels (Falco tinnunculus). Voles mark their runaways with urine and faeces, which are visible in ultraviolet light. Wild kestrels brought into captivity were able to detect vole scent marks in ultraviolet light but not in visible light. In the field, kestrels hunted preferentially near ex…
Nest mounds of red wood ants ( Formicaaquilonia ): hot spots for litter-dwelling earthworms
2017
A previously undocumented association between earthworms and red wood ants (Formicaaquilonia Yarr.) was found during an investigation of the influence of wood ants on the distribution and abundance of soil animals in boreal forest soil. Ant nest mounds and the surrounding soil of the ant territories were sampled. The ant nest mound surface (the uppermost 5-cm layer) harboured a much more abundant earthworm community than the surrounding soil; the biomass of the earthworms was about 7 times higher in the nests than in the soil. Dendrodrilusrubidus dominated the earthworm community in the nests, while in soils Dendrobaenaoctaedra was more abundant. Favorable temperature, moisture and pH (Ca c…
Lasius niger ants discriminate aphids based on their cuticular hydrocarbons
2011
Mutualistic interactions between organisms depend on the ability of each partner to recognize the other. In ant–aphid mutualisms, ants have to recognize whether an aphid colony is worth tending. Many aphid species can live in mutualistic associations with ants (trophobiosis), whereas others are never tended and are frequently preyed upon by ants. Since aphids often produce low amounts of honeydew when not tended by ants, the ants should be able to recognize potential trophobionts based on signals other than honeydew. Conversely, aphids should signal if they are potential trophobionts. We investigated whether ants recognize potential trophobiont aphids based on their behaviour, morphological…
Under my wing: lesser kestrels and jackdaws derive reciprocal benefits in mixed-species colonies
2011
In mixed-species assemblages, antipredator benefits for a timid species nesting close to a more pugnacious one are often reported. Advantages for the protected species are usually manifested in terms of higher reproductive success than conspecifics nesting remote to the protector species. Whether the protector species also accrues any benefit remains untested, and the species-specific behavioral traits underlying enhanced reproductive output in mixed-species associations remain poorly documented. We studied associations between lesser kestrels (Falco naumanni) and jackdaws (Corvus monedula) nesting in rural buildings in the Gela Plain (Italy). We tested for interspecific interactions of jac…
Parasite Infection and Host’s Behavior
2010
Animal behavior and parasitism are more tightly linked, from an ecological and evolutionary point of view, than commonly thought. In the past 30 years, the growing field of evolutionary parasitology has tackled both proximate and ultimate answers to the following question: Why and how should the behavior of hosts exposed to the risk of a disease or that of parasitized hosts be altered? Altered behavior may simply be a symptom of disease without obvious connection with host resistance or parasite-transmission strategies. However, natural selection may have shaped behavior to avoid infection, get rid of parasites, or limit their pathogenicity. Alternatively, manipulative parasites may alter t…