The Cycad Blue, Chilades (Luthrodes) pandava (Horsfield, [1829]) (Lepidoptera: Lycaenidae), has established a permanent hold in the central Levant (East Mediterranean)

The Cycad Blue, Chilades ( Luthrodes ) pandava (Horsfield), is an invasive butterfly species, which originated in Southeast Asia and probably arrived in Israel via Egypt and was discovered in Eilat (Israel) during 2015–2016 on cultivated Cycad plants, and then disappeared, apparently due to spraying with pesticides by the municipality in ornamental gardens. In late summer 2019, a small population was discovered in Ashkelon (Israel), a southern Mediterranean coastal city. It did not expand far out of the city and did not survive the winter of 2019–20. In September 2023, a new population was discovered in Upper Galilee (possibly having arrived southwards across the border from Lebanon) and within a few months a rapid spread of the species was observed as far south as the southern Negev desert, the Arava and Eilat. In the current study, we describe Cycad Blue biology, report the rapid expansion of the species in Israel, and discuss its future ecology. In particular, we note that the Indian DSF (dry season form) of Cycad Blue appears in Israel in the autumn (fall)-winter, which is not a dry season in Israel. This 'DSF' form is possibly seasonally induced via photoperiodic cues and is also linked to the larval host plant (LHP)'s sprouting of fresh leaves, rather than to other environmental conditions.