Biology

 Coccinellids are typically predators of Hemiptera such as aphids and scale insects, though larvae and eggs of their own species can also be important resources when alternative prey are scarce. Members of the subfamily Epilachninae are herbivores, and can be very destructive agricultural pests . While predatory species are often used as biological controlagents, introduced species of ladybirds (such as Harmonia axyridis or Coccinella septempunctata in North America) outcompete and displace native coccinellids and become pests in their own right. Coccinellids are often brightly colored to ward away potential predators.
  Mechanical stimulation (such as by predator attack) causes "reflex bleeding" in both larval and adult lady beetles, in which an alkaloid toxin is exuded through the joints of the exoskeleton, deterring feeding. Lady beetles, as well as other Coccinellids are known to spray a toxin that is venomous to certain mammals and other insects when threatened. 
  Most coccinellids overwinter as adults, aggregating on the south sides of large objects such as trees or houses during the winter months, dispersing in response to increasing day length in the spring. In Harmonia axyridis, eggs hatch in 3–4 days from clutches numbering from a few to several dozen. Depending on resource availability, the larvae pass through four instars over 10–14 days, after which pupation occurs. After a teneral period of several days, the adults become reproductively active and are able to reproduce again, although they may become reproductively quiescent if eclosing late in the season. Total life span is 1–2 years on average.