Horisme exoletata (Herrich-Schäffer, 1838) in southern Italy and description of its larva (Geometridae, Larentiinae)

We report Horisme exoletata (Herrich-Schäffer, 1838) for the first time in Continental Europe: Italy, Calabria. This is a species previously considered endemic to Sicily and Malta, and an addition to the shared fauna of the Calabria and Sicily regions. We provide data concerning the biology of this species in Malta, illustrating the caterpillar for the first time.


Introduction
During recent studies carried out in southern Italy devoted to the description of macro-moth communities inhabiting fragmented woodlots composed of thermophilic Quercus species such as Q. suber L., Q. virgiliana (Ten.) Ten. and Q. ilex L., some specimens belonging to the genus Horisme Hübner, 1825 (Geometridae) were collected. In the study area three Horisme species were previously known, H. radicaria (la Harpe, 1855), H. tersata (Denis & Schiffermüller, 1775), and H. vitalbata (Denis & Schiffermüller, 1775), but dissection of genitalia revealed that some of the collected specimens belong to a species new to the fauna of Continental Europe, H. exoletata (Herrich-Schäffer, 1838), previously considered endemic to Sicilia and Malta (Hausmann and Viidalepp 2012). The first three specimens have been collected at the beginning and at the end of October, and the fourth in mid-February.
Horisme exoletata has been described as Larentia exoletata by Herrich-Schäffer (1838) from Sicily. Its status at species level had been contradicted by Curò and Püngeler (Ragusa 1893), who erroneously considered this species to be a synonym of Cidaria tersata var. tersulata Staudinger, 1871. One century later, Bytinski-Salz (1937) described Horisme predotai from Sardinia, explicitly separating it from the Sicilian H. exoletata, but the lack of clear diagnostic characters led Prout (1938) to consider the former a junior synonym of the latter. Their correct identities have been ascertained on the basis of clear differences in the basal papilla of the juxta of male genitalia, which are larger and touch each other distally in H. exoletata, and in the spines on the bursa copulatrix of females, which have petaloid branches in H. exoletata (Raineri 1989;Hausmann and Viidalepp 2012). Genetic data based on COI barcodes supported the presence of two distinct species at a distance of 3.3% (Hausmann and Viidalepp 2012). Therefore, the records of H. exoletata for Sardinia in Turati (1911Turati ( , 1913 must be referred to H. predotai, as already suggested by Bytinski-Salz (1937) and Prout (1938).
Very few data concerning the biology of H. exoletata are available (Raineri 1989;Hausmann and Viidalepp 2012) and immature stages are still undescribed. In this paper we describe for the first time the larva, providing original data for its breeding carried out in Malta in winter 2005.

Material and methods
Horisme exoletata was detected in Continental Europe in Contrada Santa Cenere, at 86 meters above the sea level, in the municipality of Soveria Simeri, Catanzaro province, Calabria region, Italy (38.9259°N, 16.6729°E) (Fig. 1). We used a UV LED light trap (Infusino et al. 2017) activated one night every 4 weeks from July 2019 to February 2020. The trap was emptied early in the morning and collected specimens were identified in laboratory. Dissection of genitalia followed the protocol described in Parenti (2000). Identification was carried out comparing specimens and male genitalia to the iconography in Hausmann and Viidalepp (2012). Voucher specimens and a mounted slide of the genitalia (CREA-0225) are in the research collection of Lepidoptera of the Research Centre for Forestry and Wood, Rende, Italy (CREA-FL Collection).
Detailed information on the breeding of larvae is provided in the Results and Discussion section.

Distribution
In this paragraph, we report all bibliographic information on the distribution of Horisme exoletata, excluding those generic or repetitive. Furthermore, we also include in this review data from the following scientific collections: Currently the Italian distribution of H. exoletata covers the Calabria region of southern Italy, Sicily, where it was mainly found on the Madonie Mountains and in general in the Tyrrhenian part of the region, Pantelleria and Ustica Islands (Fig. 2). It was reported for the first time in Malta by De Lucca (1948), and reported again by Sammut (2000). We confirm with our data that its presence in Malta where it is very rare.

Morphology
The wing pattern of specimens collected in Calabria region matches that illustrated in Hausmann and Viidalepp (2012), with autumn specimens (Fig. 3a) smaller and darker than those collected in February (Fig. 3b). The presence of melanistic specimens on Mt. Etna (Hausmann and Viidalepp 2012) could be only due to seasonal variations, but this can only be ascertained with the availability of further material. Morphology of the male genitalia (Fig. 4) is very similar to that of illustrated Sicilian specimens (Raineri 1989; Hausmann and Viidalepp 2012), confirming the  and was in season. It is also important to note that no nearby Clematis plants have been observed at Ħaż-Żebbuġ and this valley. Larvae started feeding on the flowers of Ranunculus bullatus without problems. At first, cut food plants were provided and changed after 3 days as fungus growth soon started in plastic containers with the consequence that some larvae died. The second instar larvae were transferred to plants growing in pots to minimize losses. They fed mainly on flowers and seed heads. Larvae are nocturnal feeders and by day rest attached from the hind legs, motionless, resembling a dry stick on stems, underneath the flowers. On the 20 th of December 2005, the larvae were in the last instar, still feeding mainly on flower heads, seeds and occasionally leaves (Figs 5d, e, 6). On the 27 th of December, the larvae stopped feeding and formed a light silken cocoon on the ground between leaves. Unfortunately, no information is available on the pupa. Moths started emerging during the first week of April the following year.
Information on the feeding behaviour of adults could be misleading and the information available should be attributed to H. predotai. In fact, the feeding observations on blooming willows were carried out by Turati (1913) in Sardinia before the description of H. predotai, and thus cannot be attributed to H. exoletata, as reported in Hausmann and Viidalepp (2012).

Habitat
Horisme exoletata seems to be linked to hot and dry climate and to habitats with forest cover sometimes very scattered. It has been found at elevations from 0 to 1,200 metres above sea level (Hausmann and Viidalepp 2012), and in areas with a variable level of habitat degradation, being collected in an urban garden of Palermo (Grillo and Parenzan 1995) but also in semi-natural habitats of the Madonie Mountains. In Ustica and Pantelleria Islands it has been collected in thermophilic and xeric habitats with a highly fragmented forest cover (Fischer 2009;Fischer and Fischbacher 2012). Similarly, in Continental Italy it has been collected in a site at the border of a highly fragmented Quercus ilex woodlot, near the bed of the Simeri river covered by various cultivated plants. Near the collecting site, the undergrowth is densely covered by Smilax aspera L. (Liliaceae) but we did not find any of the larval foodplants which are likely present in the surroundings.

Phenology
Adults have been collected throughout the year, except in June. The month with the highest number of captures is October, but its presence during most of the year indicates the presence of at least three generations according to elevation, probably partially overlapping (Hausmann and Viidalepp 2012).

Conclusions
In this paper we provide the first record in Continental Europe and the first illustrations and detailed data on preimaginal stages for Horisme exoletata.
The presence of this species in Continental Italy is of great biogeographic interest. Furthermore, it increases the number of shared species between Sicily and the eastern coastal area of Calabrian region (Infusino and Scalercio 2011). H. exoletata fulfills the set of requirements of species exclusively present in Italy which share these geographic areas, the speciespreferring hot and xeric habitats. Species with these characteristics probably survived the last glaciations in relict areas of southernmost Italian regions, and successively were unable to spread northward or into the relatively colder and wetter western coast of Calabria region (Infusino and Scalercio 2011). The difficulty of colonisation in recent times of Continental Italy by Sicilian Lepidoptera populations has also been proved for butterflies (Scalercio et al. 2020).
In the future, DNA barcodes of Sicilian and Calabrian specimens of Horisme exoletata will be studied. Furthermore, we can expect that more Lepidoptera shared by Calabria and Sicily will be found as a large portion of eastern Calabria is still under-investigated.