Nutrition & Dietary Needs Flashcards

What is the significance of 'nutritional indices' such as ECD (efficiency of conversion of digested food) in insect nutritional ecology studies?

Answer: They quantify how efficiently ingested or digested food is converted to body mass

ECD and related nutritional indices (AD, ECI) are gravimetric measures used to compare food utilization efficiency across different diets and insect species.

Which feeding behavior do many adult Lepidoptera exhibit that differs markedly from their larval feeding?

Answer: Shift from solid plant tissue to liquid feeding on nectar or rotting fruit

Adult moths and butterflies typically feed on liquids (nectar, fruit juices, or water) via a coiled proboscis, in contrast to their foliage-chewing caterpillar stage.

Insects feeding on nitrogen-poor substrates such as wood often compensate by:

Answer: Relying on nitrogen-fixing gut symbionts or recycling uric acid

Wood-feeding insects like termites partner with nitrogen-fixing gut bacteria and recycle nitrogenous waste (uric acid) to compensate for the extremely low nitrogen content of wood.

What is the primary purpose of extraoral digestion as practiced by some predatory insects?

Answer: To liquefy prey externally for easy ingestion through sucking mouthparts

Predators like assassin bugs inject digestive enzymes into prey to liquefy internal tissues, which are then sucked up, bypassing the need to chew solid food.

In the context of ACE pest management, understanding a pest's nutritional needs is most directly useful for:

Answer: Designing bait formulations that exploit dietary preferences

Knowledge of a pest's dietary preferences and attractants is directly applied in designing effective bait products (e.g., protein baits for fruit flies, carbohydrate baits for ants).

Which nutritional adaptation allows monarch butterfly larvae (Danaus plexippus) to safely consume milkweed containing toxic cardenolides?

Answer: All of the above mechanisms working together

Monarchs use multiple mechanisms — target-site insensitivity, metabolic detoxification, and sequestration — to tolerate and exploit milkweed cardenolides.

When formulating an artificial diet for rearing pest insects in a laboratory, which component is most critical to include to support normal molting and development?

Answer: A dietary source of sterols

A dietary sterol source (e.g., cholesterol) is essential in artificial diets because insects cannot synthesize sterols and require them for ecdysteroid synthesis and membrane function.