Interactions among males, females and offspring in bark and ambrosia beetles: the significance of living in tunnels for the evolution of social behavior

TWO ACTIVE STAGES OF THE AMBROSIA BEETLE, Platypus quercivorus MURAYAMA ESTIMATED FROM FRASS PRODUCTION

“…As with P. quercivorus, the larvae of Austroplatypus incompertus are xylomycetophagous and pass through five larval instars (Kent and Simpson, 1992). Last (fifth) instar platypodid larvae make their own pupal chambers in all species studied, in most species they also extend the branch tunnels which are used by larvae prior to pupating (Kirkendall et al, 1997). Larval galleries of M. mutatus are short and are oriented vertically to the parental galleries (Alfaro et al, 2007).…”

“…Among polygamous species, i.e. Ips and Pityogenes, the male arrives at the host tree first and bores an entrance hole and a mating chamber in the phloem and waits for the female (Kirkendall et al, 1997). On the contrary, in monogamous species, exemplified by Scolytus, Trypodendron and Tomicus, the female arrives first, bores the entrance hole and initiates tunneling of gallery where the male will join the female (Kirkendall et al, 1997).…”

“…Ips and Pityogenes, the male arrives at the host tree first and bores an entrance hole and a mating chamber in the phloem and waits for the female (Kirkendall et al, 1997). On the contrary, in monogamous species, exemplified by Scolytus, Trypodendron and Tomicus, the female arrives first, bores the entrance hole and initiates tunneling of gallery where the male will join the female (Kirkendall et al, 1997). Megaplatypus and Platypus are exceptions for monogamous species since the males initiate boring tunnels as described for M. mutatus (=Platypus mutatus) (Alfaro et al, 2007) and P. quercivorus (Sone et al, 1998;Kobayashi and Ueda, 2002;Yamasaki et al,2007;Yamasaki and Futai, 2008;Tarno et al, 2011).…”

“…During the tunneling and laying eggs, the female has to keep and protect her eggs by blocking the tunnel (post ovipositional blocking). Blocking the tunnel entrance by the adult male or female could exclude predators and possibly help regulate microclimate, and might have a much greater effect on offspring survivorship in such species than for species which breed in large aggregations (Kirkendall et al, 1997). Post ovipositional blocking may be widespread in the ambrosia beetle; in some cases, this includes blocking both during and after oviposition (Kirkendall et al, 1997).…”

“…Blocking the tunnel entrance by the adult male or female could exclude predators and possibly help regulate microclimate, and might have a much greater effect on offspring survivorship in such species than for species which breed in large aggregations (Kirkendall et al, 1997). Post ovipositional blocking may be widespread in the ambrosia beetle; in some cases, this includes blocking both during and after oviposition (Kirkendall et al, 1997). During oviposition of Scolytoplatypus mikado, female beetles were likely to inoculate their symbiotic fungus spores on the gallery walls.…”