Invertebrate Zoology

Collembola is a very small insect. It directly breathes through its skin by diffusion of gases.

The labium or the lower lip is the largest and most posterior of the mouth appendages.

Hepatic caecae are present in the midgut.

Pulville (cushion-like pads) are present in the posterior part of the gizzard. They have chitinous hair, which acts as a sieve once the food is ground.

6 teeth are present in the gizzard; they facilitate the grinding of food.

The caecae secrete digestive juices and pour them into the stomach.

Peritrophic membrane lines the wall of midgut. The peritrophic membrane serves several functions, including improvement of digestion, protection against mechanical and chemical damage, and serving as a barrier to infection by pathogens.

Mandibles serve as the strongest muscles in the head. Mandibles need to be very strong for crushing food between them.

The mouth parts present in cockroaches are hypognathous, i.e. mouth parts which are directed ventrally downwards.

Wood cockroaches depend on flagellates like Trichonympha for cellulose digestion.

Midgut opens into the hindgut through proctodeal valve, which regulates food flow.

B. cuenoti is believed to inhabit all species of cockroach studied till date.

In pileworm, male and female bodies explode during mating period to release sperms and eggs, respectively. This obliterates the searching for a specific mate.

Correct Answer: Young ones grow inside mother's body and eat her from inside as they grow.

Correct Answer: calcium carbonate, chitin or cartilage