Differences in oxygen consumption and diel activity as adaptations related to microhabitat in Neotropical freshwater decapods (Crustacea)

Abstract

This study evaluated oxygen consumption (MO(2)) and diel activity in Aegla longirostri, Trichodactylus panoplus and Parastacus brasiliensis (three species of freshwater decapods that occur in sympatry), under two different conditions of O(2) availability, limited and constant; and searched for the existence of a relationship between these two variables. The Kruskal-Wallis test showed that in all the species, MO(2) was higher under constant O(2) availability; T. panoplus and P. brasiliensis showed an oxygen-dependent pattern, while A. longirostri showed higher MO(2) values and less variation in the values between the treatments, indicating a higher and more oxygen-independent metabolism. P. brasiliensis was more active in constant O(2). A. longirostri was more active in limited O(2) and did not show a clear diel activity in any case, showing behavioral changes when in unfavorable conditions. The Spearman's rank correlation analysis did not indicate any relationship between MO(2) and activity. These results indicate a higher metabolism in A. longirostri. The less demanding metabolisms of P. brasiliensis and T. panoplus allow these species to occupy environments that are unavailable to A. longirostri due to differences in dissolved-oxygen concentrations.

Diversity and conservation status of Aegla spp. (Anomura, Aeglidae): an update

“…Aeglids live preferentially in clean waters (BondBuckup and Buckup, 1994), presenting a high demand for oxygen (Dalosto and Santos, 2011), and thus making these crustaceans potential good indicators of water quality. Policies for continental water quality control will help to protect not only the aeglids but also the limnetic fauna as a whole.…”

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

“…When exploring the area outside the burrow (9.1% of all behaviors), a crayfish would walk through the aquarium with its chelipeds held parallel to the substrate, occasionally touching it, and with very rapid movements of the antennae. This, along with the nocturnal activity and the small-sized eyes of this species (Buckup and Rossi 1980;Dalosto and Santos 2011;Dalosto et al 2013) compared to other species such as the stream-dwelling South American parastacid Samastacus spinifrons (Philippi, 1882) (Rudolph 2002), indicate that tactile orientation probably is highly important for P. brasiliensis. Our results also support statements by several investigators that P. brasiliensis is nocturnal (Dalosto and Santos 2011;Dalosto et al 2013), remaining in its burrow during the day and emerging at night to forage (Buckup , 2003.…”

“…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).…”

“…It also must be noted that these classification systems for crayfish burrowing habits (Hobbs 1942) and burrows (Horwitz and Richardson 1986) were designed specifically for North American and Australian faunas. The South American crayfish fauna possesses a disproportionately high prevalence of burrowers, and investigations of their ecology can update and refine these classification systems so that we can analyze crayfish ecology within the same framework, including burrowing crayfish from all radiations (Morrone and Lopretto 1994;Taylor 2002;Collins et al 2011;Dalosto and Santos 2011;Dalosto et al 2012Dalosto et al , 2013. Given this, it is important that the habits and basic biology of the Neotropical fauna be studied, since they remain largely unknown.…”

Opportunistic predation of fish by anomuran crabs (Crustacea, Anomura, Aeglidae) in rivers of southern Brazil

“…Its species are found in clear and well oxygenated waters of streams, rivers, lakes and stream caves; usually they are hidden under rocks and plant debris (Bond-Buckup & Buckup 1994, Bond-Buckup 2003, Bond-Buckup et al 2008, Dalosto & Santos 2011.…”