The Role of Scent-marking in Patchy and Highly Fragmented Populations of the Cabrera Vole (Microtus cabrerae Thomas, 1906)

Rodent scent-marking is often used for territorial defense and self-advertisement, and both functions often entail the continuous scent-marking of a large area with high costs. In species with highly-fragmented populations and low density, in which the likelihood of social encounters is low,the costs of continuous scent-marking might exceed the associated fitness benefits; therefore, less intensive scent-marking only to signal presence to the opposite sex may be used. This hypothesis was tested in captivity with the Cabrera vole, a species with highly fragmented and low-density populations. Firstly, to assess the unknown scent-marking behaviour of the Cabrera voles, we conducted an assay wherein voles could scent-mark a clean substrate. Both sexes marked with urine and faeces, but never with anogenital secretions, and the amount of scent-marks was not different between sexes. In the subsequent assay, voles of each sex were given the choice of scent-mark on clean substrates or on substrates previously scent-marked by males or females. Both sexes marked with urine a larger area on substrates pre-marked by the opposite sex than on substrates pre-marked by the same-sex and clean substrates; however, no differences were found in the frequency of fecal boli deposited on the three types of substrate, and no anogenital secretions were found. The clear preference of receivers to scent-mark with urine the substrate pre-marked by the opposite sex strongly suggests that Cabrera voles use urine scent-marking for inter-sexual communication, probably to increase mate-finding likelihood, rather than for territorial defense and/or self-advertisement

Considerations on the use of video playbacks as visual stimuli: The Lisbon workshop consensus

This paper is the consensus of a workshop that critically evaluated the utility and problems of video playbacks as stimuli in studies of visual behavior. We suggest that video playback is probably suitable for studying motion, shape, texture, size, and brightness. Studying color is problematic because video systems are specifically designed for humans. Any difference in color perception must lead to a different color sensation in most animals. Another potentially problematic limitation of video images is that they lack depth cues derived from stereopsis, accommodation, and motion parallax. Nonetheless, when used appropriately, video playback allows an unprecedented range of questions in visual communication to be addressed. It is important to note that most of the potential limitations of video playback are not unique to this technique but are relevant to all studies of visual signaling in animals

Olfactory Mechanisms Underlying Host-Finding by the Eucalyptus Woodborer, Phoracantha semipunctata Fab. (Coleoptera: cerambycidae)

"Sem resumo feito pelo autor";- Ecological relationships of plants and animals are universal, of fundamental importance, and paradoxical. Plants use solar energy to fix carbon, and all animal life ultimately depends on use of energy stored by plants. How can an Earth teeming with herbivores, ranging in size from aphids to elephants, be so green? Animals do not eat all plants. Somehow most plants, most of the time, manage to avoid being eaten. Charles Darwin (1859) provided the key to questions borne of this paradox in the "On the Origin of Species" (Darwin, 1987). He proposed the theory of evolutionary adaptation by natural selection. Darwin argued that plants and animals best fitted to their environments leave more offspring than other members of their species and, consequently, pass their inherited advantages on to future generations. Darwin even provided insight into the nature of plant defences and animal ability to cope with those defences. He noted that sheep of different breeds have different susceptibilities to plant poisons. The fittest herbivores have an inherited ability to cope with those plant defences, and therefore to prosper on plants that their competitors cannot eat. Plants have evolved an enormous array of mechanical and chemical defences against herbivores. Herbivores, on the other hand, evolved an array of adaptations to overcome the plant defences. As pointed out by Ehrlich and Raven (1964), "the plant-herbivore interface may be the major zone of interactions responsible for generating terrestrial organic diversity". The phytophagous insects make up a more than a quarter of all macroscopic organisms, and the plants upon which they feed make up another quarter (Bernays and Chapman, 1994). Every green plant has a set of insect herbivores feeding on its roots, steams, buds, leaves, flowers and fruits. Although there is a continuous spectrum of phytophagous insects species, from those feeding on one plant species to those feeding on a wide range of plants of different families, it is common to classify them as follows: 1) monophagous include species that feed on plants within a single genus; 2) oligophagous includes species that feed on various plants in different genera within one plant family; and 3) polvphagous refers to insects feeding on a relatively large number of plant species of different families (Bernays and Chapman, 1994). Most insects have relatively narrow range of host plant species. Out of approximately 310,000 known phytophagous insect species, about 75% are monophagous or oligophagous (Bernays and Chapman, 1994) and these will be faced with the necessity of selecting the appropriate host plant at some stage of their life cycle. The study of the behavioural mechanisms underlying the selection of a suitable host plant by phytophagous insects is a challenging endeavour, and is central to understand how the present insect-plant associations have evolved, and to know what are the proximate causes of the narrow host ranges of most phytophagous insect species. The evolutionary questions have provided motivation for the study of insect-plant interactions. At the ultimate level, insect-plant associations can be explained in terms of relative fitness of insects on their host plants and, presumably, natural selection reinforces behavioural preference for suitable plants and avoidance of unsuitable ones (Feeny, 1992). Phytophagous insects may have had a role to play in the evolution of plants, by selecting for diverse chemical and physical defences. Many ecologists believe that the current diversity of both plants and insects is, in part, a result of their co-evolution (refs. in Jermy, 1993). Through an evolutionary "arras rate" between plants and insects, the plants have evolved defences to reduce herbivore pressure whilst the insects evolved ways for overcoming some of the defences. This again had consequences in a multitude of animals at higher trophic levels. Others believe that the adaptation and diversity of the insects has tended to follow that of the plants, in this case being less important the influence of insects on the evolution of plants. In other words, it is proposed that the evolution of insect-plant associations results primarily from autonomous evolutionary events, i.e. heritable functional changes within the insects' behavioural and sensorial mechanisms would mediate changes in insect-plant associations, and the ecological factors would play a secondary role by either supporting or preventing the establishment of the new genotype with the novel plant preferences (Jermy, 1993). The study of phytophagous insect behaviour tenda to have been neglected, yet the scientific knowledge of the proximate causes of behaviour and their variation is important to answer the evolutionary questions. The behavioural changes are important adaptations to be selected when an insect shifts or widens its host range. Any morphological or physiological changes, potentially adaptive to exploit a new host plant, are inconsequent if they do not occur together with behavioural changes. Thus, knowledge, about behaviour and its variation is essential to the major evolutionary questions of insect-plant relationships. Another important motivation for studying insect-plant interactions is that specialists as well as generalist phytophagous insect species have become economically important as pests on agricultural crops. Increased concern for the environment, the continued need to minimise possible hazards from crop protection agents, and the rapid development of pesticide resistance have placed tremendous demands on, research to provide new methods of pest control. These can only be successfully implemented on the basis of a detailed knowledge about the behavioural mechanisms by which phytophagous insects select host plants. The host plant selection process consists of a sequence of behavioural responses to an array of stimuli associated with host and non-host plants (Visser, 1986). Plant secondary metabolites are important stimuli in this process. These include a wide variety of organic compounds not directly involved in the primary metabolism of plants (photosynthesis, respiration, biosynthesis of proteins), and some of them have been implicated in regulating chemical mediated interactions with other organisms acting as serniochernicals1. Several plant secondary compounds contribute to defense against various organisms, including fungal pathogens, other plants, and herbivorous animals ranging from insects to man, acting as general toxicants or biocides, or may have a specific toxic action directed at a particular target. They may also act as chemical messengers or signals with purely behavioural effect, and in many cases plant chemical defenses have become signals to herbivores for selection of suitable host plants. In phytophagous insects, volatile secondary compounds have been implicated in the process of host plant selection. These are detected at some distance from the plant, affecting insects' orientation during host-finding behaviour. They act as chemical signals that attract the insect to suitable host plants or induce avoidance reactions to unsuitable plants for feeding and/or oviposition. A largo part of insects' olfactory system is thought to be specifically involved in conveying and processing information about plant volatile compounds (Mustaparta, 1992). However, it is scarce the knowledge concerning which volatile compounds or blends of compounds affect the behaviour of phytophagous insects. There is a need to focus research on what are the plant odours (host and non-host) important in host selection of different insect species with different ranges of host plants. Attraction and avoidance are important characteristics of olfaction, and it is therefore important that chernical, signals from both host and non-host plants are identified and studied, as regard their behavioural effect on insects and how such chemo-sensorial input is detected and processed. Semiochemicals that regulate insect-plant interactions have long been seen to have potential for developing new methods of pest management, e.g. through the exploitation of plant secondary metabolism for modification of insect behaviour, or to develop resistant crop cultivars (Pickett et al., 1991; Hallahan et al., 1992). The resistance of some agricultural crops varieties results in many cases from plant chemical features that have an effect on the insect behaviour, however the resistant plants have often been developed without knowledge about what modifies the behaviour. With a greater knowledge about the mechanisms by which the insects select host plants, many more resistant varieties can be developed. The eucalyptus woodborer, Phoracantha semipunctata Fabricius, is a cerambycid of Australian origin that has a range of host plants restricted to species mainly of Eucalyptus (Myrtaceae). It has been introduced to several regions of the world following the introduction of Eucalyptus for ornamental purposes or economic exploitation of its wood and essential oils. Whereas this insect species is of no economic importance in Australia, it has become a severe pest of eucalyptus plantations in, the introduced regions, including Portugal and several other Mediterranean countries (e.g. Spain, Italy, Marrocco and Tunísia). In Portugal, P. semipunctata was detected for the first time in the península of Setúbal in 1980 (Figo, 1981). Since then, the populations have increased dramatically and have spread throughout nearly all eucalyptus plantations of the country, causing significant economic losses for the growers and the pule paper industry, mainly in the central and southern regions of Portugal. P. semipunctata males and females fly at dusk and during the night in search for mates and oviposition sites. The females oviposit in bark cracks or under loose bark, preferentially on recently felled or weakened trees. Tree damage is caused by the larvae feeding on the bark. Heavy infestations result in the destruction of cambium and phloem tissues along the trunk leading to the death of the tree (Chararas, 1969; Drinkwater, 1975; Scriven et aL, 1986). Current methods of P. semipunctata control exploit the extraordinary ability of females to colonise recently felled trees. Log traps for the eggs have been used by Eucalyptus growers in order to .V gr reduce the beetles' population size of the next generation (e.g. Egea, 1982; Tirado, 1984, 1990). Some authors have suggested a role for the odour of Eucalyptus in host plant selection by P. semipunctata (Powell, 1978; Hanks et al., 1993); however this has never been thoroughly investigated

Dyadic Relationship and Quality of Life Patients with Chronic Kidney Disease

AbstractIintroduction:Chronic Renal insufficiency (CRI) and dialysis treatment lead to a succession of situations for kidney chronic patient, which compromises his aspect, not only physically, and psychologically, with personal, family and social repercussions.Objective:(1) to verify the existence of differences of dyadic adjustment (DA) according to renal replacement treatment (RRT) and (2) verify the existence of differences quality of life (QOL) in accordance with the RRT.Methods:This is a cross-sectional study of a descriptive nature through surveys, exploratory and correlational. The sample consisted of 125 participants. Of these, 31 were to be made RRT by automated peritoneal dialysis (APD) and 94 hemodialysis (HD). Participants were selected from three renal centers: (1) Centro Renal da Prelada (Porto, Portugal), (2) Centrodial (S. João da Madeira, Portugal) and Centro Renal da Misericórdia de Paredes (Paredes, Portugal). The study was carried out for 6 months. The following instruments were applied: Socio-demographic and clinical questionnaire (SDCQ), Dyadic Adjustment Scale (DAS), World Health Organization Quality of Life (WHOQOL-Bref).Results:The results demonstrate the existence of statistically significant differences between the type of RRT and most areas of QOL, as well as the existence of statistically significant differences between the subscales of the DAS evaluated and the type of RRT.Conclusion:The present study demonstrates a greater commitment in terms of QOL of individuals undergoing treatment for HD when compared with those subjected to APD. It turns out, also, that DA is most strongly perceived by patients in APD than with HD

The role of scent-marking in patchy and highly fragmented populations of the Cabrera ole (Microtus cabrerae Thomas, 1906)

Rodent scent-marking is often used for territorial defence and self-advertisement, and both functions often entail the continuous scent-marking of a large area with high costs. In species with highly-fragmented populations and low density, in which the likelihood of social encounters is low, the costs of continuous scent-marking might exceed the associated fitness benefits; therefore, less intensive scent-marking only to signal presence to the opposite sex may be used. This hypothesis was tested in captivity with the Cabrera vole, a species with highly fragmented and low-density populations. Firstly, to assess the unknown scent-marking behaviour of the Cabrera voles, we conducted an assay wherein voles could scent-mark a clean substrate. Both sexes marked with urine and faeces, but never with anogenital secretions, and the amount of scent-marks was not different between sexes. In the subsequent assay, voles of each sex were given the choice of scent-mark on clean substrates or on substrates previously scent-marked by males or females. Both sexes marked with urine a larger area on substrates pre-marked by the opposite sex than on substrates pre-marked by the same-sex and clean substrates; however, no differences were found in the frequency of fecal boli deposited on the three types of substrate, and no anogenital secretions were found. The clear preference of receivers to scent-mark with urine the substrate pre-marked by the opposite sex strongly suggests that Cabrera voles use urine scent-marking for inter-sexual communication, probably to increase mate-finding likelihood, rather than for territorial defense and/or self-advertisement

The role of male visual and chemical cues on the activation of female courtship behaviour in the sex-role reversed peacock blenny

Chemical cues during courtship in peacock blenny Salaria pavo did not add significantly to the response of visual stimuli and females did not court when a male was not visible. The results showed that female S. pavo courtship behaviour was elicited exclusively by male visual features and not by a multicomponent signal in different sensory modalities. The time spent by females courting the male and exhibiting the nuptial colouration during visual trials correlated with the size of the male’s crest, suggesting a signalling function for this trait. Alternative hypothesis for the function of the putative pheromones released by the male’s anal gland are discussed. Evidence that female sexual motivation decreases towards the end of the breeding season is also provided, which should be considered in future mate choice experiments

The effect of pair bonding in Cabrera vole’s scent marking

The Cabrera vole (Microtus cabrerae) is a rare rodent living in patchy grassy areas of the Iberian Peninsula where unpaired individuals of both sexes use scent marking primarily to increase their mate-finding likelihood. Cabrera voles establish long-term pair bonds with opposite-sex conspecifics constituting a breeding pair, which is expected to reduce the efforts in searching for a new mate. Under such circumstances, scent marking as a strategy to increase mate-finding likelihood became useless. Accordingly, we hypothesise that pair bonded Cabrera voles suppress mate-finding scent marking to reduce energetic costs and predation risk. To test this hypothesis, we compared scent-marking behaviour towards a clean substrate, in both paired and non-paired voles. No differences were found in the scent marks’ type and the amount of marks placed by voles in both conditions. We also analysed the scent-marking behaviour of both sex pair bonded voles when exposed simultaneously to a clean substrate, a substrate pre-marked by males and a substrate pre-marked by females. We found no significant differences in scent-marks (urine-marked area and number of faecal boli) across the three types of substrate types. In accordance with our prediction, these results suggest that pair bonded Cabrera voles did not use scent marking for mate finding, thus providing further support to the existence of a monogamous mating strategy. Furthermore, our results fail to support the use of scent marking for territorial defence purposes