The adult beetles are relatively large, ranging between 2 and 4 centimetres (1 and 1+1⁄2 inches) long, and are usually a rusty red colour—but many colour variants exist and have often been classified as different species (e.g., R. vulneratus).

Weevil larvae can excavate holes in the trunks of palm trees up to 1 metre (3.3 ft) long, thereby weakening and eventually killing the host plant.

[4] Additional infestations have been located in Malta, Italy (Tuscany, Sicily, Campania, Sardinia, Lazio, Marche, Puglia and Liguria), Croatia and Montenegro.

[8] It was reported in the United States at Laguna Beach, California late in 2010[9][10] but this was a misidentification of the closely related species, R. vulneratus, and it did not become established.

[12] Primarily due to the existence of numerous color forms across their ranges, the taxonomy and classification of red palm weevils has undergone a number of changes in understanding and circumscription.

As such, the information in the literature should be viewed as a compilation of data which may apply to both species, depending primarily upon the biogeography; accordingly, the vast majority of publications presumably do refer to R. ferrugineus rather than vulneratus, as the former is by far the most widely invasive.

The most recent genus-level revision in 1966[13] recognized two species of red palm weevil, ferrugineus and vulneratus, and for decades these were interpreted as separate taxa.

[15] The native range of this species is considered to include Bangladesh, Cambodia, China, India, Japan, Laos, Pakistan, Philippines, Sri Lanka, Taiwan, and Vietnam; records from Indonesia, Malaysia, Myanmar, Singapore, and Thailand largely or exclusively refer to R.

[15] R. ferrugineus has now been reported and confirmed from Albania, Algeria, Aruba, Bahrain, Bosnia and Herzegovina, Croatia, Curaçao, Cyprus, Egypt, France (incl.

Sicily and Sardinia), Jordan, Kuwait, Libya, Malta, Monaco, Montenegro, Morocco, Oman, Palestine, Portugal (incl.

Records from Australia, Papua New Guinea, Samoa, the Solomon Islands, and Vanuatu[6] have not been confirmed and are likely to be specimens of R. bilineatus, a closely related species indigenous to the region.

[16]: 245  Although the weevil was first reported on coconut in Southeast Asia, it has gained a foothold on date palm over the last two decades in several Middle Eastern countries, and then expanded its range to Africa and Europe.

[19] All known hosts of R. ferrugineus as compiled from sources by CABI ISC are: Areca catechu, Arenga pinnata, Borassus flabellifer, Brahea armata, B. edulis, Butia capitata, Calamus merrillii, Caryota cumingii, C. maxima, C. urens, Chamaerops humilis, Cocos nucifera, Corypha umbraculifera, C. utan, Elaeis guineensis, Howea forsteriana, Jubaea chilensis, Livistona chinensis, L. decora, Metroxylon sagu, Phoenix canariensis, P. dactylifera (date palm), P. sylvestris, Roystonea regia, Sabal palmetto, Trachycarpus fortunei, Washingtonia filifera, and W.

The adult female lays approximately two hundred eggs on new growth in the crown of the palm, at the base of young leaves, or in open lesions on the plant.

[citation needed] The neonate larvae are yellow-white, segmented, legless, and have a chitinous head capsule that is a darker brown than the rest of the body.

Upon completion of larval development, the larva will sometimes emerge from the trunk of the tree, and build a pupal case of fiber extracted from the galleries inside the palm.

Recent research has been conducted using electronic listening devices or dogs trained to recognize the scent of weevils or palm decay to detect infestations at low densities earlier in the process.

[citation needed] For early detection, bioacoustic analysis may be implemented by inserting a sensitive microphone into the tree and recording any produced sounds.