Reproduction and resource utilization of the ambrosia beetle, Xylosandrus mutilatus, in field and experimental populations

Abstract

The reproduction process of the ambrosia beetle, Xylosandrus mutilatus (BLANDFORD) (Coleoptera: Scolytidae), was examined by successive censuses of field populations and by artificial rearing experiments. The reproductive strategy is discussed in relation to utilization of fungal resources, the amount of which was evaluated by total gallery length (main gallery and side galleries) for the field populations or fungal area in the laboratory. Fecundity of mother adults increased with the expansion of gallery systems for cultivating their associated fungi. The number of offspring also depended on the amount of fungal resource, whereas the variation of female body size within a brood was not affected by the fungal amount. The body size apparently declined with delay in larval feeding period expressed as the order of pupation and eclosion in the field and with decreasing fungal area per larva in the laboratory. These results suggested that the combination of resource‐dependent oviposition by a mother beetle and dominant resource utilization by earlier‐hatched individuals in a brood can contribute to the efficient production of larger females when resources are limited.

Reproduction of the ambrosia beetle, Xyleborus pfeili (Ratzeburg) (Col., Scolytidae), on semi‐artificial diet

“…For some species of ambrosia beetles, the processes of reproduction and gallery construction in the wood of host trees were reported in detail (e.g. K ajimura and H ijii , 1994b; S one et al., 1998). However, the studies have struggled with the difficulty of studying the complex, three‐dimensional gallery system in the wood.…”

Evaluation ofLitchi chinensisfor Host Status toXyleborus glabratus(Coleoptera: Curculionidae: Scolytinae) and Susceptibility to Laurel Wilt Disease

“…This selective behavior for large woody hosts would be adaptive for X. glabratus, since larger diam trees could physically allow for larger gallery formations (and more extensive fungal gardens) within the sapwood, which would facilitate increased beetle reproduction. A positive correlation between gallery length and number of progeny has been demonstrated previously for other ambrosia beetles, including Xylosandrus mutilatus Blandford (Karimura & Hijii 1994) and Xyleborus pfeili (Mizuno & Kajimura 2002). Recent research indicates that host diam is a visual host-seeking cue used by female X. glabratus (Mayfield & Brownie 2013), but most likely effective when accompanied by appropriate chemical cues.…”

Effects of ingredients and structure of semi-artificial diet on the reproduction of an ambrosia beetle, Xyleborus pfeili (Ratzeburg) (Coleoptera: Curculionidae: Scolytinae)

“…The only difference among diets F, G, and H is in the amount of potato starch: diet H has the highest starch content (Table 1). These results demonstrate clearly that a mother beetle is capable of manipulating her fecundity according to the expected quantity of the food resource (ambrosia fungus) by expanding the available space (i.e., the length of the gallery system), which is also shown in X. mutilatus (Kajimura and Hijii, 1994), in response to the quality of the diet (here, the starch content).…”

“…Reproduction and gallery construction by some species of scolytine ambrosia beetles in host trees have been studied in detail by splitting and examining infested wood (e.g., Kinuura and Hijii, 1991;Kajimura and Hijii, 1994). However, the results obtained from this field data vary widely because of non-homogeneous natural conditions.…”