irruption

n. rushing in, breaking in; intrusion, invasion, raid; sudden growth in the number of animals in an area (Ecology)

Irruptive growth, sometimes called Malthusian growth, is a growth pattern defined by population explosions and subsequent sharp population crashes, or diebacks. It is an extension of the Malthusian growth model and can occur when populations overshoot their carrying capacity, a phenomenon typically associated with r-strategists. Populations which exhibit irruptive growth do not stabilize around their carrying capacity, a feature of logistic growth and common to K-strategists.
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Noun
1. a sudden violent entrance; a bursting in; "the recent irruption of bad manners"
(hypernym) entrance, entering, entry, ingress, incoming
(derivation) intrude, irrupt
2. a sudden sharp increase in the relative numbers of a population
(hypernym) population growth
3. a sudden violent spontaneous occurrence (usually of some undesirable condition); "the outbreak of hostilities"
(synonym) outbreak, eruption
(hypernym) happening, occurrence, natural event
(hyponym) epidemic
(derivation) erupt, irrupt, flare up, flare, break open, burst out

n. irruption, breaking, storming, brusting

(n.)
A sudden and violent inroad, or entrance of invaders; as, the irruptions of the Goths into Italy.
  

(n.)
A bursting in; a sudden, violent rushing into a place; as, irruptions of the sea.