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The ecological success of social insects is frequently ascribed to improvements in task performance due to division of labour amongst workers. While much research has focused on improvements associated with lifetime task specialization, members of colonies can specialize on a given task over shorter time periods. Eusocial bees in particular must collect pollen and nectar rewards to survive, but most workers appear to mix collection of both rewards over their lifetimes. We asked whether bumblebees specialize over timescales shorter than their lifetime. We also explored factors that govern such patterns, and asked whether reward specialists made more foraging bouts than generalists. In particular, we described antennal morphology and size of all foragers in a single colony and related these factors to each forager's complete foraging history, obtained using radio frequency identification (RFID). Only a small proportion of foragers were lifetime specialists; nevertheless, >50% of foragers specialized daily on a given reward. Contrary to expectations, daily and lifetime reward specialists were not better foragers (being neither larger nor making more bouts); larger bees with more antennal olfactory sensilla made more bouts, but were not more specialized. We discuss causes and functions of short and long-term patterns of specialization for bumblebee colonies.

<p><strong>The escalating extinction of wildlife puts a high pressure on the standard of ex situ conservation. Some animals may spend several generations in captivity which may affect their natural behaviors and also a future reintroduction into the wild. Observations of animal behavior among captive animals are crucial for the understanding of ex situ conservation effects on behavior and in order to introduce and improve environmental enrichment. This study investigates activity and enclosure use of a sand cat (<em>Felis margarita</em>) at Parken zoo in Eskilstuna Sweden. Direct observations of behavior and movements were carried out and audience impact was also analyzed. The sand cat in the present study showed no behavioural response to the audience but it had some effect on his location in the enclosure. I also found that he was more active during late afternoon after feeding time and that he slept most during the forenoon. He used the whole enclosure to some extent but he spent most of his time in the cave, the front and the middle of the enclosure. Although he did not show any typical stereotypic behavior he had some odd habits that could probably be prevented through environmental enrichment. </strong><strong></strong></p>

No description available.

The escalating extinction of wildlife puts a high pressure on the standard of ex situ conservation. Some animals may spend several generations in captivity which may affect their natural behaviors and also a future reintroduction into the wild. Observations of animal behavior among captive animals are crucial for the understanding of ex situ conservation effects on behavior and in order to introduce and improve environmental enrichment. This study investigates activity and enclosure use of a sand cat (Felis margarita) at Parken zoo in Eskilstuna Sweden. Direct observations of behavior and movements were carried out and audience impact was also analyzed. The sand cat in the present study showed no behavioural response to the audience but it had some effect on his location in the enclosure. I also found that he was more active during late afternoon after feeding time and that he slept most during the forenoon. He used the whole enclosure to some extent but he spent most of his time in the cave, the front and the middle of the enclosure. Although he did not show any typical stereotypic behavior he had some odd habits that could probably be prevented through environmental enrichment.

The role of semiochemicals in the behaviour and biology of <I>Lepeophtheirus salmonis</I> was investigated using a range of techniques. The potential use of semiochemicals in the behavioural ecology of mobile stages was examined using longitudinal monitoring and experimental manipulation of laboratory reared single cohort populations. The chronic and long term effects of separation from the host were also investigated using similar populations. The nature and chemosensory capability of the sense system of the parasite was assessed through morphological and ultrastructural studies. Finally, the nature of potential chemical stimuli during initial copepodid settlement, pair formation and mating, and host re-attachment of mobile stages, was examined using both <I>in vitro</I> and <I>in vivo</I> techniques. Longitudinal monitoring of populations created a model for mobile development and the timing and processes of pair formation and mating. There was evidence of a hierarchy of pair formation between female stages, periods of strong mate competition between males, and many factors within the processes were defined. Survival off the host was strongly related to the developmental stage and/or size of the louse; with adult females surviving for the longest and preadult I males for the shortest periods. The ability of adult males to re-attach and subsequently persist on the host was significantly reduced after only 72 hours of separation. Very few potential chemosensory setae were found on the appendages examined, the exception to this being the antennule. Two distinct populations of setae on the distal (14 setae) and proximal (27 setae) articles of the antennule demonstrated a wide range of morphology. The internal organisation, innervation and ultrastructure of these antennular setae was examined in detail. The setae could be divided into at least 6 distinct categories, when the internal data were combined with the external morphology.

From all the species that arrive to a novel environment, very few manage to form a viable population. The guppy, a very successful invader, is a highly social species that performs some of its vital tasks (e.g., foraging, avoiding predators) in groups. This thesis aimed to quantify heterospecific association benefits that enhance invasion success. Interactions between invaders and natives could be one of the environmental characteristics of a place that increase its risk of invasion. I evaluated the tendency of an invasive species to associate with native individuals with similar ecological requirements. I tested the hypothesis that invaders gain exploring, acquisition of information and foraging benefits when socializing with natives. In these experiments I used the guppy as the invasive model species and endangered native Mexican topminnows (Poeciliopsis infans, Skiffia bilineata, Ameca splendens, Zoogoneticus tequila, Xenotoca eiseni and Girardinichthys viviparous). I found that guppies shoal with other species in Trinidad (Poecilia picta and Poecilia sphenops), where they are native (Chapter 2) and that this trait remains when they are invasive (Chapter 3). Guppies are equally willing to explore novel environments when accompanied by heterospecifics or conspecifics. Guppies are more willing to explore complex environments than simple ones. Moreover, when exploring simple environments they have a higher association tendency, regardless of the partner' species (Chapter 4), which could lead them to acquire the benefits of grouping behaviour and avoid Allee effects - the disadvantages of being part of a small group. In the contexts in which they were tested guppies gained as much information by associating with heterospecifics as with conspecifics (Chapter 5). Finally, I found that when shoaling in bigger shoals guppies are able to locate food faster and spent more time foraging. The benefits of increased shoal size were maintained when the additional guppies were replaced with heterospecifics. However, they derive more benefits from the species they are more willing to associate with (Chapter 6). These results uncover a mechanism enabling founding individuals to survive during the most vulnerable phase of an invasion and help explain why guppies have established viable populations in many parts of Mexico as well as in every continent except Antarctica.

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