Which of the following groups lays egg rafts that are desiccation susceptible?

Which of the following groups lays egg rafts that are desiccation susceptible?

• A. Aedes and Psorophora
• B. Anopheles
• C. Culex and Culiseta
• D. All groups

Answer: (C)

Egg survival through dry periods is strongly tied to how the eggs are laid. When eggs are deposited as a raft on the water, they’re exposed to air as the water level fluctuates, and drying out can quickly damage or kill the embryos inside the raft. Groups that lay egg rafts on the water therefore have eggs that are particularly susceptible to desiccation. This is characteristic of Culex and Culiseta, whose eggs are laid in rafts on the water surface and are not highly resistant to drying, making them desiccation susceptible. In contrast, many Aedes eggs are laid on moist surfaces and are known for high desiccation resistance, allowing them to survive dry spells until flooding occurs. Anopheles lays eggs singly rather than in rafts, so the desiccation issue associated with raft eggs doesn’t apply in the same way. Thus, the group that lays desiccation-susceptible egg rafts is Culex and Culiseta.

Egg survival through dry periods is strongly tied to how the eggs are laid. When eggs are deposited as a raft on the water, they’re exposed to air as the water level fluctuates, and drying out can quickly damage or kill the embryos inside the raft. Groups that lay egg rafts on the water therefore have eggs that are particularly susceptible to desiccation. This is characteristic of Culex and Culiseta, whose eggs are laid in rafts on the water surface and are not highly resistant to drying, making them desiccation susceptible.

In contrast, many Aedes eggs are laid on moist surfaces and are known for high desiccation resistance, allowing them to survive dry spells until flooding occurs. Anopheles lays eggs singly rather than in rafts, so the desiccation issue associated with raft eggs doesn’t apply in the same way. Thus, the group that lays desiccation-susceptible egg rafts is Culex and Culiseta.