ACE-SAP

Freeze tolerance in larvae of the winter-active Diamesa mendotae Muttkowski (Diptera: Chironomidae): a contrast to adult strategy for survival at low temperatures.

BIBLIOGRAFIA

Nominativo Autori	BOUCHARD R.W. Jr., CARRILLO M.A., KELLS S.A., FERRINGTON L.C. Jr.
Anno	2006
Titolo	Freeze tolerance in larvae of the winter-active Diamesa mendotae Muttkowski (Diptera: Chironomidae): a contrast to adult strategy for survival at low temperatures.
Rivista	HYDROBIOLOGIA
Edizione	SPRINGER, DORDRECHT, PAYS-BAS, 2006.
Serie Volume	568:403-416
Parole chiave / Key words	ZOOLOGIA
Riassunto / Abstract	The winter-active Diamesa mendotae Muttkowski (Diptera: Chironomidae) is freeze intolerant in the adult stage with a low mean supercooling point (SCP) of ∼-20 °C. However, cold-hardiness strategies for immatures of this species are unknown. In this study, we measured SCP values for D. mendotae larvae, pupae and adults using surface-contact thermometry. In addition, the lower lethal temperature (LLT) was determined for the larval stage. The mean SCPs for larvae (-7.4 °C) and pupae (-9.1 °C) were relatively high compared to adults (-19.7 °C). Our results indicate that the larvae of D. mendotae are freeze tolerant with a LLT99 (-25.4 °C), ∼-10 °C lower than their minimum SCP (-15.6 °C). Freeze tolerance in these larvae may be a strategy to provide protection from short-term exposures to ice crystals or to permit diapause within frozen substrates. The change in cold-hardiness strategy from freeze tolerant to freeze intolerant between the larval and adult stages of this species is likely a result of the different habitats occupied by these two life stages.