No abstract

Three habitats, each containing a diflferent form (rainforest, coastal and dry tropics) of the twining vine Tinospora smilacina, and a fourth with two of these forms were routinely sampled between 1986 and 1989 for larvae of fruitpiercing moths, to ascertain spatial and temporal utilization of this plant, Othreis fullonia and Othreis materna occurred on all forms in all habitats, predominantly between November and March for the former and January to June for the latter. Although Rhytia cocalus utilized two forms of T. smilacina it preferred the rainforest habitat to which Othreis jordani and Khadira aurantia were essentially confined. While the degree of cohabitation between any two moth species was greatest in the drier inland habitat, where only O. materna and O. fullonia occurred during a limited season, there was considerable temporal separation of any two species utilizing T. smilacina in any habitat. Field and laboratory evaluation of alternative menisperm hosts suggested O. fullonia, O. fordani and K. aurantia were generalists while O. materna and R. cocalus confined their feeding to the genus Tinospora. The differential habitat affinities and host plant acceptance of these moths are pertinent to their variable seasonal activity, local importance and general pest status.

Fruit-piercing moths are significant pests of a range of fruit crops throughout much of the world's tropics and subtropics. Feeding damage by the adult moths is most widely reported in varieties of citrus. In the years 2003 and 2004, fruit-piercing moth activity was observed regularly at night in citrus crops in northeast Australia, to determine the level of maturity (based on rind colour) and soundness of fruit attacked. 'Navelina' navel and 'Washington' navel orange, grapefruit and mixed citrus crops were assessed, and fruit was rated and placed into five categories: green, colouring, ripe, overripe and damaged. There were no statistical differences in the percentage of fruit attacked in each category across crops. However, within the individual crops significant proportions of green 'Navelina' fruit (58.7%) and green mixed citrus (57.1%) were attacked in 2004. Among all the crops assessed, 25.1% of moth feeding occurred on overripe or damaged fruit. Crops started to be attacked at least 8 weeks before picking, but in two crops there were large influxes of moths (reaching 27 and 35 moths/100 trees, respectively) immediately before harvest. Moth activity was most intense between late February and late March. Eudocima fullonia (Clerck) represented 79.1% of all moths recorded on fruit, with Eudocima materna (L.), Eudocima salaminia (Cramer) and Serrodes campana (Guen.) the only other species observed capable of inflicting primary damage.Our results suggest that growers should monitor moth activity from 8 weeks before harvest and consider remedial action if moth numbers increase substantially as the crop matures or there is a history of moth problems. The number of fruit pickings could be increased to progressively remove ripe fruit or early harvest of the entire crop contemplated if late influxes of moths are known.

Lychee (Litchi chinensis Sonn.) and carambola (Averrhoa carambola L.) fruit, either attacked by fruitpiercing moths or undamaged, were compared on a number of occasions for weight, moisture percentage, softness, colour, �Brix, and pH, to profile fruit susceptibility in North Queensland. Height at which fruit were damaged on a tree and the tree's position in an orchard were also considered. On average 88.8% of moths inflicting damage to all fruit were Othreis fullonia (Clerck). In both crops, fruit in outer rows were more prone to attack than elsewhere in an orchard, indicating that orchard layout, trap crops, and attractive baits could all be considered to counteract these pests. No other characteristic differed significantly (P>0.05) between damaged and adjacent undamaged lychees. In damaged lychees, �Brix ranged from 11.0 to 22.8 and pH varied from 3.3 to 4.8. Highly significant (P<0.001) differences in fruit weight, colour, �Brix, and pH were recorded between damaged and undamaged carambolas; riper fruit were attacked on any individual occasion. Total soluble solids ranged from 5.2 to 11.8 �Brix in damaged carambolas and pH varied from 2.5 to 4.4. Some comparisons between cultivars were undertaken in each crop.

Mating frequency in groups of Dacus tryoni which had been either warm‐acclimated or cold‐acclimated were compared in temperature regimes ranging from just above mating‐threshold to optimal. Cold‐acclimation appeared to suppress initial mating ability of mature insects of both sexes to an extent which depended upon the acclimation regime used. The most favourable cold‐acclimation regime produced flies which in certain circumstances were able to mate at an initial frequency similar to that of warm‐acclimated flies. In no mating regime was initial mating significantly more frequent in any cold‐acclimated group than it was in any warm‐acclimated group. In most cases warm‐acclimated flies in a given regime mated at high frequency for 1–2 days, whereas the cold‐acclimated flies mated at low frequency for a greater number of days. In all cases, cold‐acclimated flies accumulated a similar or significantly lower total number of matings than warm‐acclimated groups. In experiments in which both warm‐acclimated and cold‐acclimated males competed for cold‐acclimated females, the warm‐acclimated males always out‐competed the cold‐acclimated males in two mild (near optimal) regimes. In a relatively harsh (near torpor threshold) regime, there was no significant difference in the competitive abilities of cold‐acclimated and warm‐acclimated males. The relevance of these results to possible acclimation procedures used in control campaigns involving release of sterile males is discussed.