Submitted to: Archives of Insect Biochemistry and Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2001
Publication Date: 5/15/2001
Interpretive Summary: Phosphatases are important enzymes involved with digestion, excretion, membrane transport and cytolysis. This study examined phosphatase activity in developing, prediapausing and diapausing Colorado potato beetles and the hormones that regulate these enzymes. In general phosphatase levels are low during diapause, but treatment with juvenile hormone or a peptide hormone that stimulates juvenile hormone synthesis increases phosphatase levels. This gives us a better understanding of the diapause state and provides us with information useful for the development of storage techniques for beneficial insects utilizing cold storage and/or diapause.
Technical Abstract: Acid (ACP) and alkaline phosphatase (ALP) activities in relation to adult development and diapause were examined in membrane-bound (m-ACP or m-ALP) and soluble (s-ACP or s-ALP) extractions of midgut, hindgut and Malpighian tubules of the Colorado potato beetle, Leptinotarsa decemlineata (Say). The s-ACP activity was higher than m-ACP from all tested sources and developmental profiles of the enzymatic activity were different between long- and short-day beetles and varied among tissue sources. The highest s-ACP activity was found in the midgut content followed by Malpighian tubules, hindgut and midgut tissues from both long- and short-day imagines. Short-day adults showed higher s-ALP activity in the midgut content and Malpighian tubules (except for day 1) while long-day adults contained higher m-ALP activity in both midgut tissue and hindgut. The highest s-ALP activity was observed in Malpighian tubules followed by midgut content, midgut tissue and hindgut. Treating short-day diapausing beetles with JHA (pyriproxyfen) or allatotropin had a significant inducive effect on both ACP and ALP activities in all tissues examined. Treatment with 20-HE alone did not increase ACP activity in any tissue, but did increase ALP activities in all tissues except m-ALP in the midgut. Furthermore, JHA was also able to enhance and/or modulate the effect of 20-HE treatment.