Butterflies Do Not Alter Conspecific Avoidance in Response to Variation in Density

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Insect Ecology

Background:

• High population densities often lead to increased intraspecific competition and negative performance effects.
• Life history strategies, such as increased investment per offspring, may evolve to mitigate competition costs.
• Immobile juvenile stages can exacerbate competition costs, prompting females to adopt strategies like careful oviposition site selection.

Purpose of the Study:

• To test if conspecific density cues during juvenile and adult stages alter life history strategies in *Pieris rapae* butterflies.
• To investigate whether high-density exposure leads to changes in fecundity and oviposition avoidance behavior.
• To determine if *Pieris rapae* females exhibit a flexible or fixed strategy for conspecific avoidance.

Main Methods:

• A 2x2 factorial design was employed to assess the effects of low and high conspecific density during larval and adult stages.
• The study examined butterfly fecundity and conspecific avoidance behavior during oviposition.
• Female *Pieris rapae* butterflies were exposed to different density conditions across their life cycle.

Main Results:

• Past conspecific density cues had no significant effect on either fecundity or oviposition avoidance behavior.
• All butterflies exhibited similar, low levels of conspecific avoidance during oviposition, irrespective of prior density experience.
• Fecundity levels were consistent across all experimental groups.

Conclusions:

• *Pieris rapae* females employ a fixed strategy for conspecific avoidance in oviposition decisions.
• Past density information does not influence current life history strategy or reproductive investment in this species.
• Conspecific density per se may not be a reliable predictor of current competition levels, thus not driving adaptive strategy changes.