Search results for "Predators"

Body size increase in insular rodent populations: A role for predators?

2002

Insular mammalian populations living in areas of small size are often characterized by a drastic change in body mass compared to related continental populations or species. Generally, small mammals (less than 100 g) evolve into giant forms while large mammals (up to 100 g) evolve into dwarf forms. These changes, coupled with changes in other life, behavioural, physiological or demographic traits are referred to generally as the insular syndrome. We tested in this study the relative contribution of three factors - area of island, numbers of competitor species and number of predator species - to changes in body size of the woodmouse (Apodemus sylvaticus) in the Western Mediterranean Sea. Our …

Biological protection against grape berry moths. A review

2018

International audience; Grape is a major crop, covering 7.5 M ha worldwide, that is currently being confronted with three main challenges: intensive pesticide use that must be reduced, invasion by new pests/diseases, and climate change. The biological control of pests and vectors would help address these challenges. Here, we review the scientific literature on the biological control of grape moths by macroorganisms (excluding nematodes). Two components, biological control with an active human role, mainly using biocontrol agents through inundation or inoculation, and conservation biological control, are considered. The major points are the following. (1) Tortricid grape moths seriously dama…

Ontogenetic trophic segregation between two threatened smooth-hound sharks in the Central Mediterranean Sea

2020

AbstractElasmobranchs are among the species most threatened by overfishing and a large body of evidence reports their decline around the world. As they are large predators occupying the highest levels of marine food webs, their removal can alter the trophic web dynamic through predatory release effects and trophic cascade. Suitable management of threatened shark species requires a good understanding of their behaviour and feeding ecology. In this study we provide one of the first assessments of the trophic ecology of the “vulnerable” smooth-hounds Mustelus mustelus and M. punctulatus in the Central Mediterranean Sea, based on stomach contents and stable isotope analyses. Ontogenetic diet ch…

The biological control applied in Citrus orchards against harmful exotic pests in Sicily (Italy)

2018

The citrus groves are injured by infestations caused by indigenous species or old and new phytophagous introduced. Several problems have found in the biological control a optimal solution that allowed a considerable reduction in the use of chemical products. In fact, applications of programs using biological methods has been more successful on citrus than in any other cropping system. Sicily (Italy), due to its location in the Mediterranean Sea, represents an island particularly rich flora and fauna with a characteristic biodiversity different from those of other countries and regions of Italy. It produces about 60% of the national citrus production with more areas of organic citrus groves.…

Littoral-pelagic zone food web interactions in fishless, highly humic Lake Mekkojärvi

2007

Nesting behaviour and description of mature larva of Lindenius albilabris (Fabricius, 1793) (Hymenoptera: Crabronidae)

2022

Nesting habits of the digger wasp Lindenius albilabris (Fabricius, 1793) at two localities in Poland were studied. The female hunts nymphs or adults of plant bugs Lygus rugulipennis Poppius, 1911 and L. pratensis (Linnaeus, 1758), depositing up to 10 individuals per cell, depending on their size. Nests are built in a wide variety of sandy habitats, on dirt roads, and in wastelands. The nest consists of a 10–12 cm long main burrow and one to three cells. Males are usually found on flowers of wild carrots Achillea millefolium, Daucus carota, Peucedanum oreoselinum, Pimpinella sp. and Tanacetum vulgare. The nest kleptoparasite Metopia argyrocephala was recorded in nests of this species. The ma…

Supplementary data to: Context-dependent coloration of prey and predator decision making in contrasting light environments

2021

A big question in behavioural ecology is what drives diversity of colour signals. The dataset covers the testing of the context-dependent predator selection on prey coloration. In the first experiment, detectability of artificial visual stimuli to blue tits (Cyanistes caeruleus) was tested by manipulating stimulus luminance and chromatic context of the background. In the second experiment, the effect of two light environments on the survival of aposematic, colour polymorphic wood tiger moth (Arctia plantaginis) was tested. For detailed description of the material, methods, and results of the study, see the article.

Comparison of wormlion behavior under man-made and natural shelters: urban wormlions more strongly prefer shaded, fine-sand microhabitats, construct …

2019

Abstract Urban habitats differ from their natural surroundings in various aspects, such as a higher temperature and a distinct species composition. It is therefore not surprising that animal behavior too differs between these habitat types. We studied the foraging and habitat selection behavior of a pit-building predator, a wormlion, originating from either an urban or a more natural site. Wormlions occur in nature under structures that provide shelter from sunlight and rain, such as caves, and are also common in cities, occurring under artificial shelters. Wormlions construct pit-traps to hunt arthropods, and the pits constructed by urban wormlions were larger than those constructed by wor…

Colour alone matters : no predator generalization among morphs of an aposematic moth

2018

Local warning colour polymorphism, frequently observed in aposematic organisms, is evolutionarily puzzling. This is because variation in aposematic signals is expected to be selected against due to predators' difficulties associating several signals with a given unprofitable prey. One possible explanation for the existence of such variation is predator generalization, which occurs when predators learn to avoid one form and consequently avoid other sufficiently similar forms, relaxing selection for monomorphic signals. We tested this hypothesis by exposing the three different colour morphs of the aposematic wood tiger moth, Arctia plantaginis, existing in Finland to local wild-caught predato…

Multimodal Aposematic Defenses Through the Predation Sequence

2021

Aposematic organisms warn predators of their unprofitability using a combination of defenses, including visual warning signals, startling sounds, noxious odors, or aversive tastes. Using multiple lines of defense can help prey avoid predators by stimulating multiple senses and/or by acting at different stages of predation. We tested the efficacy of three lines of defense (color, smell, taste) during the predation sequence of aposematic wood tiger moths (Arctia plantaginis) using blue tit (Cyanistes caeruleus) predators. Moths with two hindwing phenotypes (genotypes: WW/Wy = white, yy = yellow) were manipulated to have defense fluid with aversive smell (methoxypyrazines), body tissues with a…