[Edited_by_A._Ciancio,_C.N.R.,_Bari,_Italy_and_K.(Bookos.org)

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M.S.T. ABBAS
3.2.3. Locomotion
Flight of the weevils is restricted to day time and they have never been observed
as attracted by light traps (Nirula, 1956). Al-Khatri and Abd-Allah (2003)
studied the daily active periods of R. ferrugineus in date palm plantations in
Oman, using the pheromone traps. They found that the weevils had two periods
of activity, the first between 6 and 9 am and the second between 6 and 9 pm
(sunrise in that area during the period of the study was at 6:15 am and sunset
was at 5:50 pm). The weevils were noticed to have no activity during the periods
between 9 am and 3 pm and between midnight to 3 am. Similarly, Gunawardena
and Bandarage (1995) reported that the periods of RPW activity in Sri Lanka
were between 6 and 8 am and between 6 and 8 pm.
RPW adults are capable of flying as well as crawling. When they are thrown
in the air they fly away in a circle with a buzzing noise and quickly disappear,
sometimes landing shortly and boring into the soil. It is believed that the insect
is capable of either flying to a long distance or being carried by the winds. It was
noticed that when a weevil was attracted to a pheromone trap it landed at less
than 1 m apart from the trap, then crawled until reaching it (personal
observation). Chinchilla, Oehlschlager, and Gonzaler (1993) reported that the
average flight of R. ferrugineus adults was around 500 m per day and a small
portion of the insect migrated up to 1 km per day. Abbas, Hanounik, Shahdad,
and Al-Bogham (2006) found that when marked RPWs were released in date
palm plantations, some of them were captured by pheromone traps in other
plantations, 1–7 km apart from the release area. Most of such weevils were
captured 3–5 days post release.
4. NATURAL ENEMIES
There are few records about the occurrence of natural enemies of R. ferrugineus,
which might be attributed to the cryptic habitat of the eggs, larvae and pupae
which protects them from such natural enemies.
4.1. Parasitoids
Scolia erratica (Hym.: Scoliidae) was reported as an ectoparasitoid of R. ferrugineus
larvae (Nirula, 1956). However, no biological studies on this parasitoid have
been reported. In Brazil, Moura, Mariau, and Delabie (1993) and Moura,
Resende, and Vilela (1995) reported the tachinid Paratheresia menezesi as a
larval-pupal parasitoid of R. palmarum and many individuals of the parasitoid
adults emerged from a single pupa. However, attempts were carried out to rear
this parasitoid on R. ferrugineus in the laboratory, but the results were
unsuccessful (unpublished). Nirula (1956) mentioned that both RPW pupae and
adults were attacked by an unknown species of parasitic mite which killed the
pupae and reduced the longevity of adults.