predators 2025

Term Paper Preparation (Entom 2011)

Class Schedule

• Friday, 14 March: How to read (and understand) a peer-reviewed scientific paper

• Friday, 21 March: How to write a popular article on science

• Friday, 28 March: Peer review session – drafting your introduction

Alcohol Consumption as Self-Medication against Blood-Borne Parasites in the Fruit Fly

Authors and Affiliation

• Neil F. Milan, Balint Z. Kacsoh, Todd A. Schlenke

• Department of Biology, Emory University, Atlanta, GA

Summary

• Plants and fungi produce toxic secondary metabolites to limit consumption.

• Herbivores like Drosophila melanogaster (fruit fly) have developed resistance to fermentation products.

• Hypothesis: Alcohol consumption may protect fruit flies from parasitoid wasps.

• Findings: Ethanol reduces wasp oviposition and increases fly survival, suggesting alcohol acts as an antiwasp medicine.

Results and Discussion

• Natural ethanol levels in D. melanogaster habitats:

  • Up to 6% in rotting fruits, 11% in wine seepages.

  • Moderate ethanol consumption (less than 4%): increases fly fitness.

  • Higher concentrations (>4%): increased mortality.

• Comparison of parasitoid wasps:

  • Leptopilina boulardi (specialist) vs L. heterotoma (generalist).

  • Drosophila exhibited higher ethanol knockdown resistance than both wasps.

• Study showed that wasp oviposition was significantly reduced on fly larvae grown on 6% ethanol food.

• Ethanol hinders wasp reproductive success by making the environment hostile.

• Ethanol can help infected flies by exposing wasp offspring in the hemocoel to moderate ethanol levels.

Learning Outcomes by Topic

• Understand insect orders primarily consisting of predatory species.

• Examine morphological and behavioral adaptations of predatory insects.

• Explore concepts of extra-oral digestion in predatory insects.

Percent of Insect Species

• Approximate distribution: 10% predatory.

Phylogenetic Distribution

• Consists of various orders including Pterygota, Insecta, Polyneoptera, and others. Predators can be rare or common within different orders.

Morphological Adaptations to Predation

• Eyes: Enhanced visual acuity.

• Legs: Adapted for mobility and prey capture.

• Mouthparts: Specialized for predation (e.g., hooks, claws).

Mechanisms of Prey Location

• Sit-and-wait predators (e.g., tiger beetles, ant-lions).

• Active hunting: Use visual and olfactory cues (e.g., lady bugs).

• Lures: Species like Bolitophila and Arachnocampa use bioluminescence to attract prey.

Specific Predators and Their Strategies

• Antlions: Predators with specialized tactics to trap prey.

• Predatory Katydids in Australia: Mimic cicada calls to attract male cicadas.

Extra-Oral Digestion

• Used by 80% of predatory insects.

• Involves injecting digestion enzymes into prey to liquidize tissue for feeding.

• Advantages include capturing larger prey and rapid killing.

Key Takeaways from the Lecture

• Understand the diversity of predatory insects and their ecological roles.

• Recognize that predatory insects make up about 10% of known insect species.

• Note the importance of predators in biological control and their adaptations.

• Examples of innovative predatory behavior and feeding strategies.