Papers by maria cristina lorenzi
Journal of Insect Behavior, Oct 30, 2012
This is an author version of the contribution published on: Questa è la versione dell'autore dell... more This is an author version of the contribution published on: Questa è la versione dell'autore dell'opera:[Journal of
Journal of Insect Behavior, Jan 4, 2014
In primitively eusocial insects, air temperature is the environmental factor that primarily affec... more In primitively eusocial insects, air temperature is the environmental factor that primarily affects colony cycle. Several studies demonstrated interspecific differences in the adaptation of eusocial insects to local air temperature. Nevertheless, studies on intraspecific adaptations are rare. In this study, we investigate the influence of air temperature on local adaptations in behavior and colony productivity of Polistes biglumis foundresses living in warm and cold temperate zones. We hypothesized that foundresses from warm temperate zones would show a higher activity level compared to those from cold temperate zones before brood emergence, based on differences in air temperature between the two zones. After brood emergence, we expected a reduced foundress activity level in the warm climate zone, due to workers' help. In contrast, foundresses living in the cold-climate zone, which do not produce workers, were expected to remain active throughout the nesting season. We also hypothesized that colony productivity was higher in warm-climate colonies. As expected, warm-climate foundresses reduced their activity level after brood emergence and, with their relatively large number of workers, continued egg production throughout the nesting season. Further studies are necessary to assess if these intraspecific differences are attributable to phenotypic plasticity or genetic divergence.
Redia-Giornale Di Zoologia, 2003
Polistes biglumis is a species that in Southern Europe lives at high altitude where generally col... more Polistes biglumis is a species that in Southern Europe lives at high altitude where generally cold temperatures exert a selective pressure. Colonies of P. biglumis may be parasitized by the obligate and permanent social parasite P. atrimandibularis and suffer a drastic reduction in fitness. Locally, parasite prevalence is high and parasitism costs to hosts are elevated; under these conditions hosts are selected to evolve counter-adaptations against parasites. Comparing the behaviour of P. biglumis females from three populations under different combinations of selective pressures (cold temperature and social parasitism) we show how different selective pressures operate and differentiate the life cycle and behaviour of local populations.
Journal of Insect Behavior, 2014
In primitively eusocial insects, air temperature is the environmental factor that primarily affec... more In primitively eusocial insects, air temperature is the environmental factor that primarily affects colony cycle. Several studies demonstrated interspecific differences in the adaptation of eusocial insects to local air temperature. Nevertheless, studies on intraspecific adaptations are rare. In this study, we investigate the influence of air temperature on local adaptations in behavior and colony productivity of Polistes biglumis foundresses living in warm and cold temperate zones. We hypothesized that foundresses from warm temperate zones would show a higher activity level compared to those from cold temperate zones before brood emergence, based on differences in air temperature between the two zones. After brood emergence, we expected a reduced foundress activity level in the warm climate zone, due to workers' help. In contrast, foundresses living in the cold-climate zone, which do not produce workers, were expected to remain active throughout the nesting season. We also hypothesized that colony productivity was higher in warm-climate colonies. As expected, warm-climate foundresses reduced their activity level after brood emergence and, with their relatively large number of workers, continued egg production throughout the nesting season. Further studies are necessary to assess if these intraspecific differences are attributable to phenotypic plasticity or genetic divergence.
Journal of Insect Behavior, 2012
This is an author version of the contribution published on: Questa è la versione dell'autore dell... more This is an author version of the contribution published on: Questa è la versione dell'autore dell'opera:[Journal of
Current Zoology, 2014
Nestmate recognition codes show remarkable chemical complexity, involving multiple biochemical pa... more Nestmate recognition codes show remarkable chemical complexity, involving multiple biochemical pathways. This complexity provides the opportunity to evaluate the ecological and social conditions that favor the evolution of complex signaling. We investigated how the chemical signatures of three populations of the social paper wasp Polistes biglumis differed in terms of concentration of hydrocarbons, proportions of branched hydrocarbons and overall variation. We tested whether the variation in chemical signatures among populations could be explained by the prevalence of social parasites or whether this was just an effect of local abiotic conditions which influenced the composition of the hydrocarbon cuticular layer. We studied the chemical signature in three populations in which obligate social parasites differed in the selection pressures they imposed on host populations. Within each population, we restricted our analyses to non-parasitized hosts, to avoid potential short-term effect...
Bioacoustics
HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific r... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
In outcrossing hermaphrodites with unilateral mating, where for each mating interaction one indiv... more In outcrossing hermaphrodites with unilateral mating, where for each mating interaction one individual assumes the female role and the other the male role, each individual must take a sexual role opposite to that of its partner. In the polychaete worm <i>Ophryotrocha diadema</i>, the decision on sexual role is likely at stake during the day-long courtship. Here we describe, for the first time, courtship and pseudocopulation in this species, quantify their pre-copulatory behavior, and search for behavioral traits predicting the prospective sexual role (i.e., behavioral sexual dimorphism), by analyzing the courtship behavior of pairs of worms during the day preceding a mating event. We did not find any behavioral cue predicting the sexual role worms were to play; partners' pre-copulatory behaviors were qualitatively and quantitatively symmetrical. We interpret this as the outcome of a war of attrition where partners share the preference for the same sexual role, and bo...
Encyclopedia of Evolutionary Psychological Science, 2021
Evolutionary Biology, 2014
Labile sex expression is considered to play a key role in the evolution of breeding systems and i... more Labile sex expression is considered to play a key role in the evolution of breeding systems and in the transition from hermaphroditism to dioecy, according to the evolutionary models proposed for plants. While in hermaphrodites sex allocation within the individual can be plastically adjusted in response to social environment, in dioecious species it is predicted to be fixed. However, labile sex expression in the form of gender plasticity can still be present in dioecious species of animals with environmental sex determination. It is still unclear how gender plasticity is involved in the evolution of breeding systems and what its role is in the transition from hermaphroditism to dioecy. We assessed the degree of plasticity in gender expression in three dioecious species of polychaete worms of the genus Ophryotrocha. We found sexual polymorphism and plasticity in sex expression during the juvenile phase to be a response to social environment. The majority of juveniles reared with an adult female or male expressed the gender opposite of that of the partner, so as to form heterosexual pairs. On the basis of these findings we outline a possible evolutionary pathway of the transition from hermaphroditism to dioecy in the genus Ophryotrocha.
Encyclopedia of Evolutionary Psychological Science, 2016
Social Recognition in Invertebrates, 2015
Social recognition has rarely received attention in the studies on annelids. This is not surprisi... more Social recognition has rarely received attention in the studies on annelids. This is not surprising since the biology of behavioral interactions in annelids is mostly unexplored. Only few pheromones have been identified, which function as cues in mate recognition and gamete release. Many annelids use chemical and visual cues to locate partners and classify them according to mating status, body size, or oocyte ripeness. In some hermaphroditic polychaete worms and leeches the ability to recognize the quality of potential partners seem to be very refined, especially in relation to the ability to assess the number of competitors over mating. These examples suggest that sexual selection might have favored individual ability to assess conspecific numerosity accurately and vary their male and female resource allocation (sex allocation) accordingly. Finally, annelids can estimate whether they are related to their potential partners and whether they belong to the same or a different population, which again result in adjustments of their reproductive allocation. We suggest that sexual selection is likely to be responsible for the evolution of the ability to assess mate quality and social group size because sex allocation adjustments are favored by sexual selection.
Behavioral Ecology and Sociobiology, 2014
Parasite-induced alterations in host behaviour have been reported in a large number of taxa. Howe... more Parasite-induced alterations in host behaviour have been reported in a large number of taxa. However, some parasites are better than others to exploit the resources offered by their hosts. To date, our understanding of the extent to which some obligate parasites exploit social insect colonies is still limited. In this study, we examined parasite-mediated behavioural alterations of Polistes biglumis wasps parasitized by the obligate social parasite P. atrimandibularis by comparing host female-activity in parasitized and non-parasitized colonies. Host foundresses foraged more and rested less in parasitized than in non-parasitized colonies. Next, we used short-term parasite removal experiments to investigate how social parasites manipulate their hosts. These experiments allowed us to confute the alternative hypothesis that changes in host behaviour were the result of changes in colony needs (usually greater in parasitized than non-parasitized colonies). Parasitized host-foundresses foraged more and their adult female offspring rested less when social parasites were on the nest rather than after their removal. P. atrimandibularis may use behavioural interactions (such as antennation and trophallaxis) to manipulate host activities, rather than visual, acoustic, or chemical signals as other parasites do.
The American Naturalist, 2010
Sexual selection is often quantified using Bateman gradients, which represent sex-specific regres... more Sexual selection is often quantified using Bateman gradients, which represent sex-specific regression slopes of reproductive success on mating success and thus describe the expected fitness returns from mating more often. Although the analytical framework for Bateman gradients aimed at covering all sexual systems, empirical studies are biased toward separate-sex organisms, probably because important characteristics of other systems remain incompletely treated. Our synthesis complements the existing Bateman gradient approach with three essential reproductive features of simultaneous hermaphrodites. First, mating in one sex may affect fitness via the opposite sex, for example, through energetic trade-offs. We integrate cross-sex selection effects and show how they help characterizing sexually mutualistic versus antagonistic selection. Second, male and female mating successes may be correlated, complicating the interpretation of Bateman gradients. We show how to quantify the impact of this correlation on sexual selection and propose a principal component analysis on male and female mating success to facilitate interpretation. Third, self-fertilization is accounted for by adding selfed progeny as a separate category of reproductive success to analyses of Bateman gradients. Finally, using a worked example from the snail Biomphalaria glabrata, we illustrate how the extended analytical framework can enhance our understanding of sexual selection in hermaphroditic animals and plants.
Journal of Insect Physiology, 2012
Social insect colonies contain attractive resources for many organisms. Cleptoparasites sneak int... more Social insect colonies contain attractive resources for many organisms. Cleptoparasites sneak into their nests and steal food resources. Social parasites sneak into their social organisations and exploit them for reproduction. Both cleptoparasites and social parasites overcome the ability of social insects to detect intruders, which is mainly based on chemoreception. Here we compared the chemical strategies of social parasites and cleptoparasites that target the same host and analyse the implication of the results for the understanding of nestmate recognition mechanisms. The social parasitic wasp Polistes atrimandibularis (Hymenoptera: Vespidae), and the cleptoparasitic velvet ant Mutilla europaea (Hymenoptera: Mutillidae), both target the colonies of the paper wasp Polistes biglumis (Hymenoptera: Vespidae). There is no chemical mimicry with hosts in the cuticular chemical profiles of velvet ants and pre-invasion social parasites, but both have lower concentrations of recognition cues (chemical insignificance) and lower proportions of branched alkanes than their hosts. Additionally, they both have larger proportions of alkenes than their hosts. In contrast, post-invasion obligate social parasites have proportions of branched hydrocarbons as large as those of their hosts and their overall cuticular profiles resemble those of their hosts. These results suggest that the chemical strategies for evading host detection vary according to the lifestyles of the parasites. Cleptoparasites and pre-invasion social parasites that sneak into host colonies limit host overaggression by having few recognition cues, whereas post-invasion social parasites that sneak into their host social structure facilitate social integration by chemical mimicry with colony members.
Journal of Insect Behavior, 1995
One hundred twenty-five colonies of a population of the montane, haplometrotic, paper wasp Polist... more One hundred twenty-five colonies of a population of the montane, haplometrotic, paper wasp Polistes biglumis bimaculatus were marked for identification and then periodically surveyed during an entire summer period. This made it possible to record intraspecific nest usurpations (both single and multiple) and to observe associations between two females, defined here as "late associations ". Both usurpation and late association occurred primarily in the latter half of the preemergence period. Some evidence suggests that a foundress usurps a conspecific nest as a consequence of her own nest failure. After nest failure, usurpation and late association are the only available options for achieving reproductive success because, in the mountain habitat, the short summer does not allow for successful renesting. Late associations generally occurred earlier than usurpation. However, our evidence suggests that nest usurpation and late association may be the same phenomenon.
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Papers by maria cristina lorenzi