Meridialaris chiloeensis (Demoulin, 1955)

Determination of Meridialaris chiloeensis View in CoL developmental classes and voltinism through the altitudinal gradient

Nymphal developmental classes

Five distinct nymph developmental classes were obtained for M. chiloeensis by describing the developmental stage of the mesothoracic wing pads ( Taylor and Kennedy 2006) ( Figure 6 View Figure 6 ). The first developmental stage was characterised by the absence of wing pads and well-defined compound eyes, while the second primarily by the absence of wing pads. The third developmental stage presents clear wing pads on the first thoracic segment, and the fourth and fifth has wing pads with veins, expanding from the first thoracic segment to the mid portion of the second thoracic segment, and darkened wing pads, expanding to the mid portion of the third thoracic segment, respectively ( Figure 6 View Figure 6 ).

Voltinism

A high proportion of nymphs in the first developmental stage were observed during December and January, while the fifth developmental stage was more abundant through the end of March ( Figure 7 View Figure 7 ). At the same time, a high proportion of first and fifth stage nymphs were observed during April and December, respectively, showing the development of a second, slower-growing generation during the winter. Based on these population dynamics, it was estimated that it takes approximately 1185 degree-days for M. chiloeensis to complete one generation. With this estimate, we concluded that at 120 metres a.s.l., M. chiloeensis has a bivoltine life cycle, with adult emergence times occurring during January - February and March -April ( Figure 7 View Figure 7 ).