Effect of Soil Moisture on Oviposition by Childers Canegrub, Antitrogus parvulus Britton (Coleoptera: Scarabaeidae)

Abstract

Ovipositing Childers beetles, Antitrogusparvulus Britton, exhibit preference for soils of certain moisture levels. In a choice trial, A . parvulus laid most eggs in soil at approximately -74 kPa (near field capacity), no or very few eggs in soil near wilting point or drier, and few eggs in soil above field capacity (approximately -5.7 kPa). Under no-choice conditions most females retained their eggs if soil was near wilting point, oviposited immediately in soil near field capacity, and tended to extend egg-laying in soil above field capacity. Females in very wet soil laid many eggs when soil was changed to near field capacity within 3 d. After 3 d there was very little egglaying response to a change to soil near field capacity.

Phylogeography of the scarab beetle Antitrogus parvulus Britton (Coleoptera: Scarabaeidae) in south‐eastern Queensland, Australia

“…These results indicate that if females do migrate between soil patches, they fly to the nearest available soil patch (3.5–23 km, Table 3) and that genetic variation between favourable patches of soil could be due to reproductive isolation between favourable habitats. Our work supports previous observations that suggest that the females of A. parvulus are philopatric, irrespective of the distribution of soil types (Mungomery 1932; Britton 1986; Logan 1997a). Hence, the coalescence of COII to monophyly for each region (Fig.…”

“…2002a). Logan (1997a) showed that A. parvulus exhibited preference for soils with moisture contents of approximately −74 kPa (near field capacity) and, if soil conditions are unsuitable, females will retain their eggs until further rain or irrigation improves soil‐moisture conditions. This suggests that on a broader scale heterogeneous soil moisture conditions due to differences in topography, plant cover, rainfall intensity and irrigation will probably lead to variability in egg‐laying by A. parvulus and in this way oviposition might contribute to patchy larval distributions (Logan 1997a).…”

“…Logan (1997a) showed that A. parvulus exhibited preference for soils with moisture contents of approximately −74 kPa (near field capacity) and, if soil conditions are unsuitable, females will retain their eggs until further rain or irrigation improves soil‐moisture conditions. This suggests that on a broader scale heterogeneous soil moisture conditions due to differences in topography, plant cover, rainfall intensity and irrigation will probably lead to variability in egg‐laying by A. parvulus and in this way oviposition might contribute to patchy larval distributions (Logan 1997a). Our study suggests that a significant number of females are non‐volant, which indicates that if a cane farmer can eliminate an existing infestation within a field by insecticides or by the destruction of the crop and other food sources, then reinvasion by females will be slow and further outbreaks within that field are unlikely to occur.…”

“…Flights occur during the evening and mating takes place shortly thereafter (Mungomery 1932; Allsopp 2003). Such mating behaviour is typical of many Melolonthini; adults lie dormant in their pupal cells until rainfall softens the soil and adults emerge synchronously to mate; the females re‐enter the soil close to their emergence site and lay eggs within a few days (Mungomery 1932; Britton 1986; Logan 1997a; Allsopp 2003; Logan et al . 2003).…”

Grub Density of Lepidiota mansueta (Coleoptera: Scarabaeidae) in Different Habitats of the Majuli River Island of Assam, India

“…Certain levels of moisture in the soil were found essential for survival and hatching of eggs and also for the survival of the grubs especially in their first instars (Potter and Gordon, 1984). Logan (1997) reported that childers canegrub, Antitrogus parvulus laid most eggs in soil near field capacity, no or very few eggs in soil near wilting point and few eggs in soil above field capacity. Tai Hsien (1965) found that soil moisture at 20-30 per cent field capacity was optimum for egg survival.…”