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Urbanization and agriculture are strongly modifying natural ecosystems and these land use changes are now considered as major drivers of biodiversity change. Yet, some species appear to be able to deal with human-created environments. However, because these settings show altered biotic and abiotic conditions, we may expect phenotypic adjustments as a response to a life in urban and agricultural areas. In this thesis, I studied personality differences between woodland, agricultural and urban populations of the speckled wood butterfly (Pararge aegeria), a former forest specialist that successfully colonised anthropogenic habitats. Using behavioural tests that quantify variation in boldness, activity and exploration, I show that butterflies from different landscapes of origin differed regarding mean levels of boldness and syndrome structure (i.e. the correlation between personality traits). As these experiments involved laboratory-reared individuals, results suggest a genetic basis to the observed differences. The conducted experiments also shed light on environmental conditions that affect personality traits through phenotypic plasticity, including age and intraspecific interactions (i.e. male-male fights). Additionally, I show that developmental conditions affect the repeatability of behavioural traits. Using different experimental approaches, I also tested the ecological relevance of personality traits in the speckled wood butterfly. While boldness does not correlate with aspects of spatial use, more active males were more likely to win territorial fights, which may give them a fitness advantage. Together, these results provide valuable insights into the field of invertebrate personality – a group that has been rather overlooked in the context of animal personality – and they contribute to understanding the response of species to human activities., (SC - Sciences) -- UCL, 2022

Polylepis forests are endemic to the high‐Andes, with trees characterized by multi‐layered, exfoliating bark‐providing protection against harsh, high‐elevation conditions, both for individual trees and the wide array of organisms dependent on them. However, Polylepis habitat has suffered severe human‐induced land conversion and currently mainly occurs as fragmented remnants only. Here, we studied the effects of fragment size on local ambient temperature and on biomass of bark and its bark‐dwelling arthropods. We did so by comparing multiple samples at the edge and interior of both large and small fragments, while also accounting for branch size, tree width, and tree structure. Because arthropod biomass is likely to impact higher trophic levels, we also studied abundance and foraging behavior of two bird species specialized on Polylepis forest. We show that arthropod biomass was relatively higher in wider, larger trees, which were preferred for foraging by both bird species. Moreover, we show that small forest fragments are not only environmentally less buffered but are also characterized by lower amounts of bark and lower densities of bark‐dwelling arthropods than larger fragments. Our study highlights the conservation value of large trees. Also, we advise it is now timely to test to what degree restoration efforts to increase fragment size could mitigate the negative effects of reduced arthropod biomass for higher trophic levels of endemic specialist insectivores

The increasing urbanization process is hypothesized to drastically alter (semi-)natural environments with a concomitant major decline in species abundance and diversity. Yet, studies on this effect of urbanization, and the spatial scale at which it acts, are at present inconclusive due to the large heterogeneity in taxonomic groups and spatial scales at which this relationship has been investigated among studies. Comprehensive studies analysing this relationship across multiple animal groups and at multiple spatial scales are rare, hampering the assessment of how biodiversity generally responds to urbanization. We studied aquatic (cladocerans), limno-terrestrial (bdelloid rotifers) and terrestrial (butterflies, ground beetles, ground- and web spiders, macro-moths, orthopterans and snails) invertebrate groups using a hierarchical spatial design, wherein three local-scale (200 m × 200 m) urbanization levels were repeatedly sampled across three landscape-scale (3 km × 3 km) urbanization levels. We tested for local and landscape urbanization effects on abundance and species richness of each group, whereby total richness was partitioned into the average richness of local communities and the richness due to variation among local communities. Abundances of the terrestrial active dispersers declined in response to local urbanization, with reductions up to 85% for butterflies, while passive dispersers did not show any clear trend. Species richness also declined with increasing levels of urbanization, but responses were highly heterogeneous among the different groups with respect to the richness component and the spatial scale at which urbanization impacts richness. Depending on the group, species richness declined due to biotic homogenization and/or local species loss. This resulted in an overall decrease in total richness across groups in urban areas. These results provide strong support to the general negative impact of urbanization on abundance and species richness within

During the last century, the human footprint on natural ecosystems has increased strongly and human-altered habitats such as urban and agricultural areas have extended globally. Despite their negative impacts on biodiversity, these habitats offer unique opportunities to study how native species respond to novel environmental conditions. Here, we studied phenotypic divergence associated with colonization of human-altered habitats in the Speckled wood (Pararge aegeria). We reared butterflies of woodland, urban and agricultural origins under common garden conditions and we measured boldness and activity at the adult stage. Both behavioural traits were repeatable at the individual level (i.e. personality traits), but we found weak evidence for ecotype-related differences in mean boldness and activity. In line with urban areas being stressful habitats, we found that boldness and activity traits correlate in urban butterflies, while we found no such syndrome in woodland and agricultural butterflies. Our results show that urbanization can alter some aspects of personality in an insect species, but they do not support the prediction that anthropogenic habitats favour boldness. Significance statement: Human activities such as urbanization and intensive agriculture strongly alter terrestrial ecosystems and they are among the most significant threats to biodiversity. To tolerate human-dominated landscapes, many vertebrate species show behavioural shifts towards bold personalities, but similar responses remain rather overlooked in invertebrate taxa. Here, we studied the progeny of woodland, agricultural and urban Speckled woods reared under common garden conditions and we assessed their personality. We found little evidence for differences in personality traits among landscape types, but the behavioural syndrome linking boldness and activity was detected only in urban butterflies. This shows that urbanization can indeed shape some aspects of personality in invertebrates.

Most behavioural traits show plastic responses to changes in internal or external conditions. Similarly, animal personality is not necessarily fixed during an individual's lifetime, leading to age-related changes. Both individual plasticity (i.e., within-individual effect) and non-random selective (dis)appearance of behavioural types (i.e., between-individual effect) may contribute to age-related changes observed at the population level. Here, we investigated how boldness changes with age in a woodland population of the Speckled wood butterfly (Pararge aegeria L.) using a capture–mark–recapture approach. We used wing wear as an index for age and we show that fresh individuals are bolder than worn individuals. Using the subsample of recaptured butterflies, we found that this pattern is most likely driven by individual plasticity. Our design also allowed us to explore some aspects of the species' spatial ecology and how it relates to personality. We found no relationship between boldness and net displacement between successive captures, a finding which we discuss within a movement ecology framework.

info:eu-repo/semantics/published

Holding a territory is often crucial in order to acquire key resources, including mating partners. However, few studies have investigated the role of animal personality in the context of territorial conflicts and how the contest outcome itself may influence personality traits. We studied personality in male Speckled wood butterflies, Pararge aegeria, before and after territorial contests for sunspot territories. Before interactions, boldness decreased with age, while activity and exploration were only influenced by ambient conditions. Neither age nor morphology did influence the probability to win contests, but winners were more active and more explorative than losers and, moreover, males that received a red wing mark were more likely to be winners. Butterflies that lost a contest showed pronounced behavioural changes. Mean boldness increased and its repeatability was disrupted, while no such change was detected in winners. The observed boldness increase in losers may be explained by a ‘desperado effect’, though its implication for successive contests remains unknown. Given that territoriality is expected to have important consequences for reproductive success, our results suggest that personality traits may indirectly contribute to individual fitness by influencing the ability to gain access to mate-location patches.

For developing organisms, early environmental conditions are critical as they provide cues about their environment and are thus helpful to make decisions for the short and long term. As such, the early environment is known to affect several phenotypic traits, and these can persist after developmental growth. However, the role of these early environmental conditions in shaping personality traits remains largely unknown. Here, we used a reciprocal transplant experiment to explore the effect of landscape of origin versus landscape of development on boldness and activity in a butterfly, Pararge aegeria. Larvae of woodland, agricultural and urban population origins were reared in situ in their landscape of origin or under the two alternative environmental conditions. We then repeatedly quantified boldness and activity in the F1 adults under laboratory conditions. While the landscape of development appeared to have no effect on mean trait values, it affected trait repeatability through changes in among-individual variation. Additionally, males of agricultural origin had higher mean boldness scores than woodland and urban origin males. Also, average boldness declined with testing sequence in individuals of woodland origin, but not in agricultural and urban origin individuals. Overall, our results suggest that (1) conspecifics originating from distinct habitat types differ in some aspects of boldness, and (2) early developmental conditions can affect behavioural consistency without changing mean behavioural phenotypes.