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

Abstract

Background: Crayfish from the Neotropical region comprise a unique group among crustaceans. Their burrowing habits have severe consequences for many ecological, morphological, and behavioral traits. Although they are all considered true burrowers, the degree of these adaptations and their relationships to the behavioral repertoires of these crustaceans have been discussed for a long time, although with no consensus. Results: To address this situation, we performed behavioral observations of Parastacus brasiliensis in a laboratory environment. Animals (n = 7) were isolated and acclimated in experimental aquaria according to their size (two large and five smaller aquaria) and observed for seven days at four different times of the day (twice during the day and twice at night). Their behaviors were qualified and quantified. The time spent inside and outside the burrow was also observed and analyzed with a t test for paired samples. Their circadian activity was analyzed using Rayleigh's Z test. Animals spent 54.9% of the time hiding within the burrow and also remained longer in it during the day than at night. They spent more time active outside the burrow during the night. Conclusions: These results suggest that these crayfish are nocturnal and are definitely not a part of the lotic species group. This species appears to be closely associated with its burrow but can exhibit considerable activity outside of it and can therefore be classified as a secondary burrower. Although this is a laboratory study, the results may stimulate further studies on the importance of burrows to these animals and provide basic background information for new studies on these cryptic crustaceans.

Oxidative Status Profile in Different Tissues of Parastacus brasiliensis promatensis (Crustacea, Decapoda, Parastacidae) over a Seasonal Cycle

“…Crustaceans generally exhibit high levels of reproductionassociated energy demand, related to gamete formation, gonadal maturation, particularly in females, vitellogenin synthesis, and, in males, to the "active search" for mates, agonistic interactions, and even mating itself (Rosa and Nunes, 2003;Castiglioni et al, 2006;Oliveira et al, 2007;Palaoro et al, 2013;Jimenez and Kinsey, 2015).…”

How to deal with a bad neighbor? Strategies of sympatric freshwater decapods (Crustacea) for coexistence

“…Crayfish could not be sexed because this species possesses no clear sexual dimorphism, not being possible to accurately sex the animals without sacrificing them (Rudolph & Verdi, 2010;Dalosto et al, 2012Dalosto et al, , 2013. We have three reasons to argue that crayfish sex did not affect our results: 1-the lack of clear sexual dimorphism, 2-the fact that crayfish behaved uniformly in this and other studies (Dalosto et al, 2013;Palaoro et al, 2013b), which suggests that sexes do not behave differently outside of the reproductive season, and 3-the fact that we avoided the reproductive season. Size and weight for all selected animals can be seen in Table 2.…”

“…Despite being considered specialized burrowers, crayfishes of the genus Parastacus can exhibit considerable activity outside their burrows. This is true for P. brasiliensis: although it uses the burrows extensively, it also shows considerable activity outside the burrow (Fontoura & Buckup, 1989;Palaoro et al, 2013b). This has been observed both in laboratory and in the field, when the crayfishes were occurring alone.…”

“…The most commonly encountered groups are anomurans of the genus Aegla, and crayfish of the genus Parastacus (Dalosto & Santos, 2011). Some studies have suggested that aeglids are competitively superior to Neotropical crayfish, and have forced them out of optimal habitats (Riek, 1971;Dalosto & Santos, 2011;Palaoro et al, 2013b), which would result in one or more forms of segregation in natural environments. Given that aeglids are aggressive animals that occur in high densities, conversely to that which is known for Parastacus (Bueno & Bond-Buckup, 2000;Buckup, 2003, Ayres-Peres et al, 2011bDalosto et al, 2013), one would expect them to exhibit some form of segregation when they occur in sympatry.…”

How variable is agonistic behavior among crab species? A case study on freshwater anomurans (Crustacea: Decapoda: Aeglidae)

“…The antennae are known to be used during crustacean contests (e.g. Rubenstein & Hazlett, ; Ayres‐Peres et al ., ; Dalosto et al ., ), and they are used in different intensities according to the environment (Bovbjerg, ; Bruski & Dunham, ; Palaoro et al ., ). When light levels are low, crayfish tend to use their antennae more intensely both in contests and in other situations (e.g.…”