Predicting the invasive potential of the cladoceran Daphnia lumholtzi Sars, 1885 (Crustacea: Cladocera: Daphniidae) in the Neotropics: are generalists threatened and relicts protected by their life-history traits?

Invasive species are one of the major threats to biodiversity, which is aggravated in poorly known groups, such as cladocerans. Daphnia lumholtzi Sars (Cladocera: Anomopoda: Daphniidae) is currently invading the Neotropical region, and there are few records of this process. Our goal was to predict the invasive scenario for D. lumholtzi in the Neotropics using species distribution modelling and to assess the climatic overlap of the invader with the native species. We trained our MaxEnt model using occurrence records from native and invaded areas and projected it in the Neotropics. Additionally, we compared the climatic niche of some native species with the invader’s niche. Our model showed high environmental suitability in areas connected by the lowland Paraná River Basin (southwestern Brazil, eastern Argentina and Uruguay), in south-central Chile and Atlantic coastal areas. Widely distributed native species showed climatic overlap with the invader, while relict species did not. Daphnia lumholtzi thrives in warm and stable environments (e.g. the Paraná River basin), which of concern because the invader could already be spreading in that area. Native species could suffer due to climatic niche similarity, while natural barriers and local environmental conditions may protect relict species. We urge the need for further studies to understand this invasion process more fully.   </p

Overview of the mating systems of Crustacea

Due to an exceptional variety of habitats, body plans, and lifestyles, crustaceans exhibit a wide array of mating systems. Some groups engage in simple, pure- search polygamous systems in which males usually search for receptive females. In other groups, males defend valuable resources to attract and/ or guard females to ensure paternity. Some species have developed highly complex systems of harem defense polygyny and monogamy, even cases of sub- and eusociality are reported. The expression of mating systems does not seem to be uniformly correlated to taxonomic affiliation, but is rather diverse within certain groups, suggesting that the evolution of mating systems is largely facilitated by the lifestyle of the species. Despite the broad range of mating systems in crustaceans, and although some groups have been studied comparably well, there remains a lack of knowledge about the behavioral and sexual biology of many species. In the light of the high diversity of lifestyles, mating systems, and habitats of certain groups, crustacean species would be ideal models to unravel the evolution of reproductive strategies and social behaviors

Behavioural and morphological precursors predict the origin of parental care

Data and code for the phylogenetic comparative analyses conducted in the study. Please refer to README.txt for more information

Data from: How does environment influence fighting? The effects of tidal flow on resource value and fighting costs in sea anemones

An animal's decision to enter into a fight depends on the interaction between perceived resource value (V) and fighting costs (C). Both could be altered by predictable environmental fluctuations. For intertidal marine animals, such as the sea anemone Actinia equina, exposure to high flow during the tidal cycle may increase V by bringing more food. It may also increase C via energy expenditure needed to attach to the substrate. We asked whether simulated tidal cycles would alter decisions in fighting A. equina. We exposed some individuals to still water and others to simulated tidal cycles. To gain insights into V, we measured their startle responses before and after exposure to the treatments, before staging dyadic fights. Individuals exposed to flow present shorter startle responses, suggesting that flowing water indicates high V compared with still water. A higher probability of winning against no-flow individuals and longer contests between flow individuals suggests that increased V increases persistence. However, encounters between flow individuals were less likely to escalate, suggesting that C is not directly related to V. Therefore, predictable environmental cycles alter V and C, but in complex ways

Population biology of Aegla platensis (Decapoda: Anomura: Aeglidae) in a tributary of the Uruguay River, state of Rio Grande do Sul, Brazil

Aeglids are freshwater anomurans that are endemic from southern South America. While their population biology at the species-level is relatively well understood, intraspecific variation within populations has been poorly investigated. Our goal was to investigate the population biology of Aegla platensis Schmitt, 1942 from the Uruguay River Basin, and compare our data with data from other populations. We estimated biometric data, sex ratio, population density and size-class frequencies, and frequencies of ovigerous females and juveniles, from the austral spring of 2007 until autumn 2008. Sexual dimorphism was present in adults, with males being larger than females. Furthermore, males and females were significantly larger than previously recorded for the species. The overall sex ratio was 1.33:1 (male:female), and population density ranged from 1.8 (spring) to 3.83 ind.m-² (winter). Data from this population differ from published information about A. platensis in almost all parameters quantified except for the reproductive period, which happens in the coldest months, and a population structure with two distinct cohorts. Difference among studies, however, may be in part due to methodological differences and should be further investigated in order to determine their cause. In addition to different methodologies, they may result from ecological plasticity or from the fact that the different populations actually correspond to more than one species

Figures, full analyses tables and more detailed methods from How does environment influence fighting? The effects of tidal flow on resource value and fighting costs in sea anemones

One figure describing the experimental setup, the full output tables of the statistical analyses and a more thorough description of our statistical method