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Graph-theoretic connectivity analyses have received much attention in connectivity evaluation during the last few years. Here, we explore the underlying conceptual differences of various graph-theoretic connectivity measures. Based on connectivity analyses from three reserve networks in forested landscapes in Central Finland, we illustrate how these conceptual differences cause inconsistent connectivity evaluations at both the landscape and patch level. Our results also illustrate how the characteristics of the networks (patch density) may affect the performance of the different measures. Many of the connectivity measures react to changes in habitat connectivity in an ecologically undesirable manner. Patch prioritisations based on a node removal analysis were sensitive to the connectivity measure they were based on. The patch prioritisations derived from different measures showed a disparity in terms of how much weight they put on patch size versus patch location and how they value patch location. Although graphs operate at the interface of structure and function, there is still much to do for incorporating the inferred ecological process into graph structures and analyses. If graph analyses are going to be used for real-world management and conservation purposes, a more thorough understanding of the caveats and justifications of the graph-theoretic connectivity measures will be needed. [ABSTRACT FROM AUTHOR]

Conditional handicap models of sexual selection predict that sexual traits are reliable signals of male quality because they are (a) condition dependent and (b) costly to produce or maintain. In this study, my objective was to experimentally investigate whether the drumming of male Hygrolycosa rubrofasciata wolf spiders is a condition-dependent costly trait. Males court females by drumming dry leaves with their abdomen and females preferentially mate with males drumming at higher rates. I manipulated male phenotypic condition and drumming rate simultaneously by keeping males on three different food rations and either introducing or not introducing them to a female. Food ration treatment affected male condition, as males on a low food ration lost mass while males on a high food ration maintained their mass at a constant level. The manipulation of food ration affected male drumming rate: males on a low food ration had the lowest drumming rate while males on a high food ration drummed at the highest rate. Manipulation of drumming rate incurred significant fitness costs: males induced to drum at higher rates suffered higher mortality than other males. Furthermore, there was a significant female introduction by food ration by male size interaction on male survival. When induced to increase their drumming rate, large males manipulated to be in good condition survived better than large males manipulated to be in poor condition. There was no such difference in small males. When drumming rate was not increased, the slopes between males survival and size were homogeneous and weakly positive across each condition treatment. Despite the higher mortality when introduced to females, there was still a significant positive correlation between drumming rate and survival. My results demonstrate that sexual signalling in H. rubrofasciata is condition dependent and costly, thus supporting conditional handicap models of sexual selection. [ABSTRACT FROM AUTHOR]

We studied the microhabitat selection and male sexual signalling behaviour in the wolf spider Hygrolycosa rubrofasciata (Ohlert). Males strike dry leaves with their abdomen, producing an audible sexual drumming signal, and females use this signal to choose mating partners. In the field we followed male drumming rate and microhabitat selection using both the mark-recapture method and direct observations. In the laboratory we conducted an experiment on male microhabitat and drumming substrate selection. We found that in the field males were not distributed randomly among the habitat; fewer males were found in areas that had high sedge cover, low elevation, and low dry leaf cover. In the laboratory experiment, males spent more time on dry leaf substrate. Drumming rate in the field was positively correlated with dry leaf cover and in the laboratory males clearly preferred dry leaves as drumming substrate. Temperature was positively correlated with male drumming rate, and with male and female mobility. We conclude that in H. rubrofasciata male distribution and sexual signalling rate, and thus mating success, are greatly affected by environmental factors. Therefore, males may be sexually selected to make effective use of their signalling habitat by active microhabitat choice. [ABSTRACT FROM AUTHOR]

Game theoretical models predict that the main function of fighting behaviour is to assess the relative fighting ability of opponents. The sequential assessment game has often been used to investigate contests, while honest signalling theory has received much less attention. With the wolf spider Hygrolycosa rubrofasciata we investigated whether male agonistic signalling can reveal honest information about fighting ability, and how size and motivation asymmetries affect male fighting behaviour. We also determined whether male-male competition affects the courtship behaviour of the males. We found that agonistic drumming activity is an honest indicator of male fighting ability, and that relative size asymmetry and motivation to fight both contribute to the fighting ability. We also found that male-male competition decreases the courtship drumming rate of subdominant males, suggesting that male-male competition limits the opportunities for female choice. We conclude that sequential assessment and honest signalling may both be used in settling contests, and that they may be used simultaneously. [ABSTRACT FROM AUTHOR]