The Heat Shock Response Under Natural Conditions in Two Paper Wasp Species

Area of Science:

• Environmental stress physiology
• Insect molecular biology
• Ecology

Background:

• Heat shock proteins (hsps) are crucial for cellular recovery and tolerance during heat stress.
• Previous studies indicated high hsp inducibility in paper wasps under laboratory heat stress.
• Understanding hsp expression under natural environmental conditions is vital in a warming world.

Purpose of the Study:

• To investigate heat shock protein gene expression in paper wasps under natural daily temperature fluctuations.
• To compare natural hsp expression patterns with those observed in laboratory settings.
• To determine if developmental stage (larva vs. pupa) influences hsp response to environmental temperature changes.

Main Methods:

• Collected paper wasp broods (Polistes dominula, P. nimpha) from wild nests at 06:00 and 16:00.
• Measured the expression levels of three heat shock protein genes (hsp70, hsp83, hsc70).
• Correlated gene expression with natural daily temperature variations experienced in the field.

Main Results:

• Nest temperatures in July reached levels capable of significant hsp upregulation, as seen in lab studies.
• Under natural conditions, hsp induction was moderate and primarily observed in larvae.
• Pupae exhibited constant hsp expression, unaffected by daily temperature fluctuations, similar to late-afternoon larvae.

Conclusions:

• Natural temperature fluctuations induce a more moderate heat shock response in paper wasps than laboratory conditions.
• The developmental stage significantly impacts the response to thermal stress, with larvae showing induction and pupae exhibiting constitutive expression.
• Field studies provide essential context for interpreting laboratory findings on heat shock protein responses.