1/14/2021: Top-down roach cull basics
As we pass the halfway point this January I take a moment to panic about everything that needs to be done by spring. The fruits of many winter endeavors won’t be reaped for many months, but, equally so, neglected tasks can cause lingering problems down the road.
Culling is not necessarily a pleasant chore for the roach keeper, but it is sometimes necessary when space is limited or pest infestation risk is high. Today’s subjects have been Byrsotria rothi and cabrerai, two species that are extremely underrated but very useful in a pinch and easy to keep. When their numbers get too high, fresh adult die offs can occur, and within the last 2 years these colonies have been producing full steam after taking a break for a year.
Usually in these situations I do what I call a “top-down” cull; this involves taking out any deformed, damaged, or old adults while leaving fresher or healthier ones, much as natural forces may do in a wild population. I must resist the immense urge to select only the biggest individuals; I try to preserve as much genetic diversity in stock not because inbreeding will weaken a colony, but so that the population mirrors the wild population from whence it came as accurately as possible. Selective breeding is an animal for a different day.
Usually I will also cull all presub and subadults as well; these tend to be stressed or damaged in these situations and their final molt has a risk of being flawed or fatal due to the prior mentioned conditions.
What this leaves is a colony of newborn to half-grown individuals and strong, vigorous, diverse adults, and usually within a few months the colony has recovered completely to a healthy previous state. The remaining culls I use as feeders for various other projects, ensuring nothing is wasted.