Behavioral repertory of Trichodactylus panoplus (Crustacea: Trichodactylidae) under laboratory conditions

Abstract

This work describes the behavioral repertory of Trichodactylus panoplus von Martens, 1869, based on the animals' diel activity and the possible substrate preference under laboratory experiments. Three experimental replicates were carried out, each using six animals (three males and three females). There were four periods of observation a day, with a total of 864 observation sessions and 144 hours of experiments. A total of 15 behavioral acts divided into five categories were recorded: feeding, exploration of the environment, immobility, social interaction, and self-grooming. The obtained results suggest that T. panoplus has greater activity during the night (p < 0.05), yet without showing an activity peak. In addition, the acceptance of food does not depend on the photoperiod. There was a significant preference for gravel as the chosen substrate. The Morisita index indicates an aggregated distribution of these animals, confirming their preference for substrate with gravel. The increase in activity at night and the preference for substrate with gravel, which can be used to disguise these individuals, would be associated to some anti-predator strategies of these crabs against visually orientated predators

Feeding spectra and activity of the freshwater crab Trichodactylus kensleyi (Decapoda: Brachyura: Trichodactylidae) at La Plata basin

“…This pattern is similar to other decapod species from inland waters, which indicates a crepuscular (dawn and dusk) feeding rhythm (Collins 1997;Williner and Collins 2002;Aguzzi et al 2005;Zimmermann et al 2009). However, there are many evidences that the presence of food at any time of the day can trigger the locomotion in decapod crustaceans even in periods of low activity (Fernandez de Miguel and Aréchiga 1994;Reigada 2002;Pontes and Arruda 2005;Sokolowicz et al 2007;Zimmermann et al 2009). Indeed, in T. kensleyi, the presence of prey items in the gut content suggests a continuous food intake and can provide clues of the movement of crabs in streams throughout the day.…”

Assessing the importance of burrows through behavioral observations of Parastacus brasiliensis, a Neotropical burrowing crayfish (Crustacea), in laboratory conditions

“…2007; Gusmão- Júnior et al 2012). It is somewhat analogous to what was assumed for the freshwater crab Trichodactylus panoplus (von Martens, 1869), which uses a strategy of immobility along with burying itself in the substrate, instead of burrowing (Zimmermann et al 2009). Alternatively, long periods within burrows can reduce interspecific competition with other freshwater decapods, such as the freshwater anomurans of the genus Aegla Leach, 1820, occasionally found in sympatry with Parastacus (Morrone andLopretto 1994, Dalosto andSantos 2011) and which are aggressive and highly mobile animals (similarly to surface water crayfish) (AyresPeres et al 2011a(AyresPeres et al , 2011bPalaoro et al 2013).…”

“…In addition, the permanent water could have prevented the animals from excavating more complex burrows (Hamr andRichardson 1994, Noro and, and thus, we cannot accurately infer about the extent to which P. brasiliensis would burrow in natural habitats. Grooming behavior, where the animal uses its chelipeds and/or pereiopods to remove epibionts and prevent body fouling, is common in many species of decapods (Bauer 1981(Bauer , 2002Zimmermann et al 2009). Grooming, presumably associated with cleaning of the body surfaces, occurred at a very low frequency (0.3%).…”

“…This procedure was followed for 7 days, with the animals being fed fish pellets every other day, alternating between day and night to avoid bias (e.g., the first time they were fed at 1200 and the next time at 2400). During nocturnal observations, red incandescent light bulbs (40 W) were employed, as decapod crustaceans have low sensitivity to this wavelength (Turra and Denadai 2003;Zimmermann et al 2009;Ayres-Peres et al 2011a). The aquarium was covered with parchment to avoid behavioral bias caused by the observer.…”

Substrate preference and settlement behaviour of the megalopa of the invasive crab Percnon gibbesi (Decapoda, Percnidae) in the Mediterranean Sea

“…An ethogram was built a priori with three different categories: direct selection, hesitation and exploration (Table 1). Hesitation and exploration are defined according to Zimmermann et al [36] (actually our hesitation corresponds to Zimmermann's immobility category) while direct selection is defined as the act of moving directly to a specific substrate after release without performing any other behaviour.…”