The systematics and biology of the New Zealand "tiger moth", genus Metacrias Meyr. (Arctiidae, Lepidoptera.)

Abstract

Studies have been made on the systematics, distribution, ecology, life history, growth, and anatomy of Metacrias erichrysa, M. huttoni and M. strategica. Reasons for regarding M. erichrysa and M. huttoni as distinct species are given, and recent glaciation is suggested as a possible explanation of their separation. The distribution pattern and method of dispersal is discussed and the differing habitats of the three species described. Features of the life history are examined with particular reference to the remarkable flightless female imago of this genus. In M. erichrysa and M. huttoni it was discovered that the first instar larvae devour the female parent, a feature recorded only once before in the Lepidoptera. Possible advantages of flightless females of this type are discussed. Growth studies include head capsule measurements of successive instars and weight measurements. A growth curve is constructed. A detailed study of the anatomy of the larva, pupa and imago is made to emphasise features of the extreme sexual dimorphism, particularly in the imago.