Reproductive traits of Glenea cantor (Coleoptera: Cerambycidae: Lamiinae).

Glenea cantor (F.) is a cerambycid species that attacks living trees of at least seven plant families in Asia, and has the potential to become an invasive pest. Here we investigated its reproductive biology in the laboratory to provide vital information for the development of pest control measures and preparation of pest risk analysis. Both sexes required a period of maturation feeding before mating, with the mean premating period of males (5.87 +/- 1.68 d) being significantly longer than that of females (4.59 +/- 2.34 d). This was a synovigenic species with the mean preoviposition and oviposition period being 13.50 +/- 3.15 d and 49.46 +/- 16.16 d, respectively. If no food was available after emergence, adult males died before reaching sexual maturation and females vanished before oviposition. Paired couples mated an average of 15.12 +/- 7.02 times; 28- to 53-d-old beetles mated significantly more frequently than younger and older ones. The mean fecundity was 133.24 +/- 9.67 eggs. The oviposition rate significantly increased in the first 5 wk of the oviposition period, peaking when females were 40- to 54-d-old, and then significantly decreased in the following weeks. Reproductive activities occurred almost exclusively during the day, with most ovipositions taking place in the morning and matings in the afternoon with some overlaps.

Phenology and laboratory rearing procedures of an Asian longicorn beetle, Glenea cantor (Coleoptera: Cerambycidae: Lamiinae).

Clenea cantor (F.) (Coleoptera: Cerambycidae: Lamiinae) is an Asian longicorn beetle whose larvae bore under the bark of living trees of at least seven plant families and enter the wood for pupation. Here, we determined the phenology of this beetle on its natural host, kapok [Bombax ceiba L. = Cossampinus malabaricus (DC.) Merr], in an uncontrolled insectary at ambient environmental conditions, and we compared the efficiency of four larval rearing procedures at 25 +/- 2 degrees C, 75 +/- 5% RH, and a photoperiod of 14:10 (L:D) h in the laboratory. It had five generations, including an overwintering generation, a year in southern China, with overlaps between generations and no diapause. Adults were present in early March-early December; eggs in early April-early December; larvae almost year-round, and pupae in mid-February-mid-April as well as mid-May-late November. All larvae of the overwintering generation and the larvae of the fourth generation that hatched in and after mid-November overwintered. The longevity of females and males was 71.94 +/- 1.21 d and 46.87 +/- 1.11 d, respectively, and mean fecundity was 106.65 +/- 3.61 eggs. Four larval rearing procedures using kapok twigs were tested: (1) 10 neonate larvae were left in the original host twig, (2) 10 neonate larvae were removed from the original bark and transferred to a new host twig, 3) 10 neonate larvae embedded in the original bark were transferred to a new host twig, and 4) a single neonate larva embedded in the original bark was transferred to a new host twig. We observed the survival of 300 neonate larvae for each rearing procedure. Approximately 81-85% of neonate larvae successfully developed to adult stage when neonate larvae were transferred together with the original bark to new host twigs; when neonate larvae were transferred without the original bark, only approximately 38% of the inoculants became adults, and when larvae were left in original twigs, approximately 52% of them reached adult stage. Resulting adults from different rearing methods and collected from the field had similar body weight and sex ratio. In terms of time, labor, and the number of resulting adults, procedure 3 is the most effective method for maintaining a laboratory colony.

Host selection and colonization strategies with evidence for a female-produced oviposition attractant in a longhorn beetle.

In longhorn beetles and many other internally feeding insects, oviposition choice by females is critical to the survival of their offspring because their larvae are incapable of moving between hosts. Here we report on the complex host selection and colonization strategies of a longhorn beetle, Glenea cantor (F.) (Coleoptera: Cerambycidae), which is an important pest of kapok trees [Bombax ceiba L.=Gossampinus malabaricus (DC.) Merr.] in southern Asia. It attacks weakened trees, eventually killing them. The typical oviposition behavioral sequence in the laboratory includes the following: oviposition site search and recognition using antennae and palpi, oviposition slit preparation with mandibles, turning body direction 180°, egg deposition with the ovipositor, and oviposition wound covering with a jelly-like material from the ovipositor. Bark moisture content significantly increases from the upper to lower sections in kapok trees. In accordance with this variation female adults select the upper section of trees first for oviposition. As infestation continues and the host becomes more weakened, ovipositing females move further down the tree for oviposition. Consequently, the larvae kill the hosts from the top down. We show that the jelly-like material or eggs or both have an olfactory role in attracting females to oviposit nearby. Our findings are important in terms of increasing our understanding of host selection and colonization mechanisms of internally feeding insects, particularly cerambycids, and the development of environmentally friendly pest management measures.