Early Hairstreak (Erora laeta) (W.H. Edwards, 1862)

Diagnosis: The female of this small species has extensive dark blue with black borders on the upperside. In the male the upperside is dark grey with a small dark blue area near the edge of the hindwing. The underside in both sexes is jade green with an irregular orange line in the middle of both wings, and has an orange margin. Wingspan: 21 to 24 mm.

Range: Erora laeta is mainly an Appalachian and New England butterfly in the U.S., extending north into four Canadian provinces. The Canadian range is a narrow band from London, Ontario, where the original type specimen was taken (it has not been seen in the London area for many years) through eastern Ontario and southern Quebec, north to Quebec City, to a few isolated localities in New Brunswick (e.g., Edmundston) and in southern Nova Scotia.

Similar Species: This is a unique species in Canada in appearance.

Early Stages: Until recently these were unknown, but they have now been described as yellowish green with dark red markings. For many years, the species has been associated with American Beech (Fagus grandifolia), and possibly also Beaked Hazelnut (Corylus cornuta), and this was confirmed in the 1980s (Klots and dos Passos, 1981). Despite this, larvae were never found on beech and females would not oviposit on the leaves. Recently Erora laeta was reared in New Brunswick; when twigs containing developing beechnuts were accidentally presented to females which had refused to oviposit on leaves, they all immediately laid eggs on the nuts. The larvae eat the husk of the nut in the early instars, then later bore into the nut and eat the developing seeds, eating two or three seeds during their lifetime (Reginald Webster, pers. comm.). This makes Beaked Hazelnut a possible alternative in localities such as northern Michigan, where laeta occurs beyond the range of Beech; the developing nuts have a rough husk and milky interior similar to beech nuts.

Description of this image follows.
Early Hairstreak (Erora laeta).
Low, Que. P.M. Catling

Abundance: Considered one of the rarest butterflies throughout its range, the Early Hairstreak occasionally appears in large numbers in particular localities. In the early 1980s, up to 50 individuals could be seen sipping moisture along a few sandy woodland roads in the Gatineau Hills of western Quebec (Layberry et al., 1982).

Flight Season: In most of its eastern North American range, it has two flights, but only one flight has been recorded in Canada, from mid-May to mid-June.

Habits: In Canada, this butterfly is associated with fairly extensive mature beech-maple forests. It is possible that it is not as rare as assumed, but that it spends most of its life around the tops of large beech trees, out of sight. It does not occur around immature beeches; this is now understandable because these do not produce nuts. It is usually seen flying very low, just a few inches above the ground, or more often sitting on the ground, probing at damp sand with its haustellum (tongue); in these circumstances it often refuses to move and can be studied or photographed from only inches away. Sometimes, however, it is as wary as any other butterfly, and on these occasions always flies away vertically into the top of the nearest tall tree. It presumably comes down to the ground only with exactly the right combination of factors, such as temperature and humidity, to sip moisture from the damp earth. Females are seen much more often than males, which is the opposite of the case with most butterflies. There are a number of instances of this mysterious butterfly appearing in collectors' nets quite by accident and unexpectedly while their nets are being swung at another insect.

Remarks: The most closely related butterfly is Erora quaderna (Hewitson), which is found from Arizona to Guatemala and feeds on oaks (Quercus spp.).

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.