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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.05.016 Byline: Marco Vannini, Elisabetta Lori, Cecilia Coffa, Sara Fratini Abstract: Individuals of Cerithidea decollata periodically migrate along mangrove trees, resting on the trunks during high water, and foraging on the surrounding muddy platform during low water. Groups, ranging from tens to hundreds of snails, aggregate on the trunks well before the incoming tide (1-2h) at a level that will not be reached by the high tide, that is, from a few centimetres (around neap tides) to over 1m (around spring tides) above the ground. We addressed two questions: (1) how can snails determine when to stop climbing and (2) how do snails determine the length of the path necessary to stop at that level. We used plastic pipes, 2m long and 20cm in diameter, along which snails crawled just as on their own trees. Experiments in which the pipes were lowered, raised or tilted indicated that snails were able to perform both tasks. Overloading the snails with lead weights showed that the estimate of the required travelling distance was probably related to the energy used to cover that distance. However, it was not possible to define how snails were able to establish the distance they needed to travel to avoid the incoming tide, although we were able to exclude any role of for visual cues or chemical marks present on substratum. Author Affiliation: (a) Department of Evolutionary Biology 'L. Pardi', University of Florence, Italy (a ) Zoological Museum of the University of Florence, 'La Specola', Italy (a ) Department of Evolutionary Biology, University of Siena, Italy Article History: Received 9 January 2008; Revised 26 March 2008; Accepted 6 May 2008 Article Note: (miscellaneous) MS. number: D-08-00018

The ability for climbing crabs of East African mangrove swamps, Sesarma leptosoma, to recognize predators visually is examined by experimentation with three dummy objects made to look like the predators. The results show that the crabs hesitated in their movements when confronted with the dummies which had the open claws of the predator. From this it can be concluded that the crabs are able to visually detect shapes and sizes and the presence of danger.

A swimming crab was studied to determine if it used landmarks to locate its refuges.

• Attitudes towards GHG mitigation and climate change adaptation are assessed. • Study subjects include sheep farmers, extension officers and scientists involved in sheep farming research. • Extension officers and sheep farmers show converging negative attitudes towards mitigation. • Beliefs and information are found to cause diverging attitudes. • Consequences on the working of the knowledge transfer chain and implications for policy design are discussed. Low innovation adoption rates in agriculture have spurred intense research on farmers' attitudes and motivations. Little attention has been paid to attitudes of other important actors in the knowledge transfer chain. Evidence indeed suggests that adoption rarely happens at the farm level, but requires the right inputs from science and extension services. Divergent attitudes among actors in the knowledge transfer chain may hence contribute to low adoption rates by transferring insufficient, outdated, irrelevant and/or incorrect information. This study is an investigation on attitudes towards climate change mitigation and adaptation of three classes of actors: sheep farmers, researchers involved in fields related to sheep farming and extension officers from private companies and public agencies. The investigation is based on data collected through self-administered questionnaires submitted to 165 participants to agricultural field days in Sardinia (Italy). The sample consists of sheep farmers (37,5%), researchers (16,4%), extension officers (32,1%) and other agricultural workers or students (14 %). In order to assess differences in attitude and identify the sources of attitudinal divergence, the study adopts Kolmogorov – Smirnov (KS) equality-of-distribution tests and Partial-least square structural equation modelling (PLS-SEM). Comparing and contrasting attitudes towards several topics related to GHG emission mitigation and adaptation to climate change reveal that researchers and extension officers have different attitudes towards innovation for mitigating GHG, that in turn depend on different information and beliefs on the causes and effects of climate change. This context is less than optimal to promote adoption of climate change mitigation or adaptation strategies. Climate change science and policy design need to recognise the complexity of knowledge transmission and the multiplicity of attitudes and beliefs that inform and affect the process. To mitigate the impact of diverging attitudes and beliefs among researchers and extension officers tailored communication strategies should avoid controversial issues and focus on benefits of innovation on farm efficiency. In turn, this would build trust and cooperation among all the actors in the knowledge transfer chain. Only when cooperation is assured, one could be confident that the information delivered to farmers is scientifically sound, relevant, value-neutral and useful in changing farmers' behaviour. [ABSTRACT FROM AUTHOR]

Abstract: The gastropod T. palustris is one of the major species responsible for leaf consumption and degration within the Indo-Pacific mangrove forests, and it strongly competes with herbivorous sesarmid crabs in consuming fallen leaves. This snail feeds at high and low tides and it is able to locate food items by means of chemical cues. The aim of this study was to assess the food preferences of T. palustris and to define its feeding strategies at low and high tides, by conducting field trials on water-borne mediated food location at high tide, grazing rate and the chemical attraction exerted by different mangrove leaves. The results showed that T. palustris was able to perceive underwater grazed leaves. In addition, we demonstrated that T. palustris consumes all the mangrove species (preferentially the Rhizophoraceae leaves) but Xilocarpus granatum. Moreover, this snail is differentially attracted to different mangrove species: the major attractive power is wielded by the rhizophoracean species and Pemphis acidula, while X. granatum does not attract this snail at all. The efficacy and adaptive value of a chemically mediated food searching strategies is unquestionable since by using this ability T. palustris can locate and reach the leaves it preferentially consumes. Moreover, T. palustris is the only macrobenthic species of East Africa mangroves able to search, detect and consume mangrove leaves at both high and low tides. Such an expanded feeding window permits T. palustris to occupy temporal niches left empty by the sesarmid crabs. [Copyright &y& Elsevier]

Scylla serrata (Decapoda: Portunidae) is a swimming crab that is widespread in the Indo-Pacific region and commonly found in estuarine and mangrove waters. An extended planktonic larval phase suggests high dispersal potential and the possibility of extensive gene flow between conspecific populations at least on a geographic mesoscale (tens to hundreds of kilometres).Intraspecific variation of the mitochondrial DNA cytochrome oxidase subunit I (mtDNA COI) gene was investigated in 77 individuals from four representative mangrove swamps of the African tropics (Kenya and Zanzibar) by means of DNA sequencing. We examined 535 base pairs (bp) and identified 24 different haplotypes. Each population sample is characterised by a single most frequent haplotype, shared among all four populations, and a small number of rare ones, typically present in only one or two individuals and representative of a specific population.Analysis of molecular variance (AMOVA), FST statistics and χ2 contingency analysis of spatial distribution of mtDNA haplotype frequencies revealed in toto a significant genetic differentiation among populations. These results could indicate that gene flow might be reduced, even between geographically close sites, despite the high potential for dispersal; anyway, at the recorded level of divergence and owing to the abundance of rare haplotypes and singletons in our data set, repeated sampling over time is necessary to establish whether the recorded pattern of genetic differentiation is stable and biologically significant.Finally, integration of our data with those reported by Gopurenko et al. [Mar. Biol. 134 (1999) 227] on S. serrata from South Africa, Red Sea and Mauritius Islands allowed to infer S. serrata population structure within a larger area of the Indian Ocean region. [Copyright &y& Elsevier]

Using a multi-dimensional ecological design, this study aimed first to analyse whether local environmental conditions can account for the spatial segregation of two Italian native decapods, the crayfish Austropotamobius italicus and the river crab Potamon fluviatile, in Central Italy freshwater ecosystems. Second, we aimed to analyse which environmental variables were more closely associated with the presence/absence of the two decapods in specific sites within their distribution area. Following a factorial design, a total of 32 sites were selected in two neighbouring geographic areas, one occupied by crayfish and one by crabs. Within each distribution area, eight streams where the decapod was present and eight where it was not present were selected. At each site, macro-invertebrate community composition and 16 abiotic variables were recorded and analysed with multi-variate methods. Variations in physical (minimum and maximum temperatures), chemical (calcium, oxygen, nitrate and nitrite) and geomorphological (substrate composition) parameters explained spatial segregation of P. Fluviatile and A. Italicus in the study area. The occurrence of crayfish reflected variations of chemistry (such as pH, calcium, nitrate and nitrite concentrations), temperature, water depth and substrate composition. On the contrary, the presence of the river crab, within its occurrence zone, was not associated to any biotic and abiotic parameters and was probably affected by anthropogenic pressure and uncontrolled harvesting. These findings provide fundamental ecological data for the maintenance of the two decapod natural populations as well as for the selection of areas and streams adequate for their reintroduction. [Copyright &y& Elsevier]

Abstract: The mangrove gastropod Cerithidea decollata feeds on the ground at low tide and climbs trunks 2–3h before the arrival of water, settling about 40cm above the level that the incoming tide will reach at High Water (between 0, at Neap Tide, and 80cm, at Spring Tide). Biological clocks can explain how snails can foresee the time of the incoming tide, but local environmental signals that are able to inform the snails how high the incoming tide will be are likely to exist. To identify the nature of these possible signals, snails were translocated to three sites within the Mida Creek (Kenya), 0.3–3km away from the site of snail collection. The study sites had a much wider tidal range than the original site (up to 160cm), were dominated by Rhizophora mucronata trees and uninhabited by C. decollata. If cueing signals were linked to the upper mangrove belt (site-specific signals), the Avicennia marina area, translocation should affect snail behaviour; conversely, we could conclude that information on the height of the incoming tide should be widely available within the whole creek (widespread signals), independently from cues linked to the home area and home site. Tests were performed by releasing the snails close to vertical plastic pipes (2m high) following a standardized procedure. Results revealed that snails, even in such unfamiliar surroundings, climbed higher and earlier on pipes where the tide level would be higher, thus allowing rejection of the hypothesis of site specific signals. Where the tide exceeded 80cm, however, snail effort was not sufficient to avoid submersion and snails had to climb higher. Hypotheses on widespread signals possibly involved in modulating the migratory behaviour of C. decollata are discussed. [Copyright &y& Elsevier]