holocyclic

Holocyclic is an adjective used in entomology, especially aphidology, to describe a life cycle that includes sexual reproduction and the production of overwintering eggs. In holocyclic species, populations typically alternate between a primary host and one or more secondary hosts, with a sexual generation giving rise to eggs that survive winter, starting a new generation in spring.

During favorable seasons, reproduction is primarily parthenogenetic on the secondary host, leading to rapid population growth; as autumn approaches, sexual morphs (males and sexual females) form and mate; the resulting eggs overwinter on the primary host before hatching in spring to produce new fundatrices that initiate the cycle again.

In contrast, anholocyclic life cycles lack the obligatory sexual phase and overwintering egg stage; reproduction is largely or entirely parthenogenetic and may continue through winter in milder climates or controlled environments. Some species can switch between holocyclic and anholocyclic strategies depending on temperature, photoperiod, and host availability.

Geographic and ecological patterns: holocyclic life cycles are common in temperate regions with distinct seasons, while anholocyclic forms are more prevalent in tropical regions and in greenhouse crops. These differences influence pest management strategies, including timing of control measures aligned with the sexual generation and egg hatching.