Influence of starvation on the larval development ofHyas araneus (Decapoda, Majidae)

Abstract

The influence of starvation on larval development of the spider crab Hyas araneus (L.) was studied in laboratory experiments. No larval stage suffering from continual lack of food had sufficient energy reserves to reach the next instar. Maximal survival times were observed at four different constant temperatures (2 °, 6 °, 12 ° and 18 °C). In general, starvation resistance decreased as temperatures increased: from 72 to 12days in the zoea-1, from 48 to 18 days in the zoea-2, and from 48 to 15 days in the megalopa stage. The length of maximal survival is of the same order of magnitude as the duration of each instar at a given temperature. "Sublethal limits" of early starvation periods were investigated at 12 °C: Zoea larvae must feed right from the beginning of their stage (at high food concentration) and for more than one fifth, approximately, of that stage to have at least some chance of surviving to the next instar, independent of further prey availability. The minimum time in which enough reserves are accumulated for successfully completing the instar without food is called "point-of-reserve-saturation" (PRS). If only this minimum period of essential initial feeding precedes starvation, development in both zoeal stages is delayed and mortality is greater, when compared to the fed control. Starvation periods beginning right after hatching of the first zoea cause a prolongation of this instar and, surprisingly, a slight shortening of the second stage. The delay in the zoea-1 increases proportionally to the length of the initial fasting period. If more than approximately 70 % of the maximum possible survival time has elapsed without food supply, the larvae become unable to recover and to moult to the second stage even when re-fed ("point-of-no-return", PNR). The conclusion, based on own observations and on literature data, is that initial feeding is of paramount importance in the early development of planktotrophic decapod larvae. Taking into account hormonal and other developmental processes during the first moult cycle, a general hypothesis is proposed to explain the key role of first food uptake as well as the response pattern of the zoea-1 stage to differential starvation periods.

Tolerance of Hyas araneus zoea I larvae to elevated seawater PCO2 despite elevated metabolic costs

“…While larvae development of some crustacean species at high latitudes comprises a lecithotrophic phase (Anger et al 2003), Arctic H. araneus larvae depend on food out of the water column for a successful development. Former studies indicated the crucial importance of a sufficient food supply for development and survival of crustacean larvae (Anger and Dawirs 1981;Dawirs 1983). Larvae in the present study were fed ad libitum to guarantee a suitable food supply, which should be consistent with natural food ability as the estimated biomass (dry mass) in Kongsfjorden is relatively high with 8.8 ± 5.1 g m -2 (Hop et al 2002).…”

Seasonal variation in starvation resistance of early larval North Sea shrimp Crangon crangon (Decapoda: Crangonidae)

“…1; for more details, cf. Anger & Dawirs 1981, Anger 1987, Staton & Sulkin 1991. In the PRS experiments, the larvae were fed from hatching for 1 to 6 d, followed by continuous starvation (Treatments F1-F6; Fig.…”

“…This critical point within larval development represents a threshold where starved and subsequently fed larvae, which still may remain alive for an extended period, cannot recover from previous nutritional stress, and lose their capability to develop further. Anger & Dawirs (1981) first demonstrated the existence of a PNR in decapod crustacean larvae. Moreover, they discovered a 'point-of-reserve-saturation' (PRS), beyond which food uptake is no longer essential for subsequent development and moulting to the following larval stage; this critical point was later found to be identical with the transition between Stages C (intermoult) and D 0 (early premoult) of the moulting cycle, and thus, was renamed 'D 0 threshold' (Anger 1987).…”

Spatio-temporal variation of planktonic decapods along the leeward coast of the Fernando de Noronha archipelago, Brazil

“…Further, this peak in nutrients, albeit at very low concentrations, could be due to a decrease in phytoplankton (Dugdale, 1967). The decrease in the phytoplankton community affects the zooplankton community (secondary consumers) directly, causing their decline (Costlow and Bookhout, 1959;Anger and Dawirs, 1981;Emmerson, 1984;Anger, 2001). Despite the higher nutrient values found at the Porto de Santo Antônio station, the amounts registered were within the expected values for oligotrophic regions (Assunção et al, 2016).…”