Using meteorological and lunar information to explain catch variability of Orthoptera and Lepidoptera from 250 W Farrow light traps MARTIN J. STEINBAUER, 1,2 ANGIE HASLEM 2 and EDWARD D. EDWARDS 3 * 1 Australian Plague Locust Commission, Canberra, ACT, Australia, 2 Department of Zoology, La Trobe University, Melbourne, Vic., Australia and 3 Australian National Insect Collection, CSIRO Entomology, Canberra, ACT, Australia Abstract. 1. Farrow light traps have been used in Australia since the 1970s to moni- tor locusts only, but catch variability has not been explained. Four light traps were operated at North Bourke, northern New South Wales, to study catch variability. 2. Habitat did not influence catch composition (non-metric multidimensional scal- ing ⁄ analyses of similarity) or similarity. Assemblages of Orthoptera differed only modestly between December and March, whereas assemblages of macrolepidoptera differed strongly between December, March and April. 3. Twenty-two species of Orthoptera were caught and seven analysed. Kruskal– Wallis ranking tests showed that the largest catches of a species of cricket were obtained when the dominant wind direction was from the SE, whereas the largest catches of three acridid species were obtained when the wind was from the NW. Catch variability of two acridids could be explained by temperature (Generalised lin- ear models); the smallest acridid by wind speed and of the cricket and two acridids by moon surface illumination (K). 4. Eighty-two species of macrolepidoptera were identified and 17 analysed. The largest catches of a noctuid were obtained when the wind was from the SW; an oeno- sandrid was only caught when the wind was from the SE or NE. Catch variability of two noctuids, an arctiid and an oenosandrid could be explained by temperature; three noctuids, an arctiid, a cossid and a psychid by relative humidity; a noctuid by wind speed; and two noctuids and two oenosandrids by K. 5. To facilitate comparisons of catches and interpret long-term population trends, catch variability should be standardised for meteorological ⁄ lunar conditions. Key words. Crickets, flight activity, insect monitoring, locusts, macrolepidop- tera, mallee eucalypt habitat, moon phase, population dynamics, River redgum riparian habitat, wind speed and direction. Introduction Insect monitoring and insect diversity surveys often require the use of some type of entomological trap. These traps catch insects either passively (Malaise and suction traps) or by attraction (bai- ted, colour and light traps). Light traps are commonly used in insect monitoring and surveys (McQuillan et al., 1998; Cunningham et al., 2005; Steinbauer & Weir, 2007; Kishimoto- Yamada et al., 2010) so it is important to understand the causes of catch variability for each type of trap and light source. Conse- quently, the influences of temperature, wind speed and moon- light on catch variability have received substantial attention (Bowden, 1973; McGeachie, 1989; Muirhead-Thomson, 1991; Yela & Holyoak, 1997; Butler et al., 1999). Despite the need to explain catch variability, in Australia, it has only been investigated for a few trap types and a small suite Correspondence: Martin J. Steinbauer, Department of Zool- ogy, La Trobe University, Melbourne, Vic. 3086, Australia. E-mail: M.Steinbauer@latrobe.edu.au *Present address: Australian National Insect Collection, CSIRO Ecosystem Sciences, GPO Box 1700, Canberra, ACT 2601, Aus- tralia. Insect Conservation and Diversity (2012) 5, 367–380 doi: 10.1111/j.1752-4598.2011.00170.x Ó 2011 The Authors Insect Conservation and Diversity Ó 2011 The Royal Entomological Society 367