Macrodactylus subspinosus
Encyclopedia
Macrodactylus subspinosus is a North America
n beetle of the family Scarabaeidae
. It is one of at least two beetles in this family known as the "rose chafer
", the other being the Europe
an Cetonia aurata. M. subspinosus occurs from Eastern Canada
to Colorado
and is considered a pest of many crops and flowers. It is given its common name of rose chafer because it eats the leaves of roses, although it also feeds on many other plants.
during its development. In late May, white-bodied larvae, about 18 millimetre (0.708661417322835 in) long, pupate after having overwintered deep in the soil. Once they have emerged from their pupal case, adults live for 3-6 weeks, during which time they will feed on plant material and mate. Their eggs are laid in sandy soils, 15 centimetres (6 in) deep, and hatch in 1-3 weeks. This new generation of larvae will feed on the roots of grasses, weeds, and some ornamental garden plants during the rest of the summer, before they burrow deep in the soil to overwinter; these larvae will emerge as adults in the following year.
, rose chafers can detect the plant compounds in the air and orient themselves in the direction of the feeding conspecific, leading to an aggregation of the beetles. Male rose chafers also orient themselves preferentially toward virgin females as opposed to mated females, though it is unknown whether they are detecting pheromone
s released by virgin females, or the release of plant volatiles induced by the feeding virgin females.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n beetle of the family Scarabaeidae
Scarabaeidae
The family Scarabaeidae as currently defined consists of over 30,000 species of beetles worldwide. The species in this large family are often called scarabs or scarab beetles. The classification of this family is fairly unstable, with numerous competing theories, and new proposals appearing quite...
. It is one of at least two beetles in this family known as the "rose chafer
Rose chafer
Cetonia aurata, known as the rose chafer, or more rarely as the green rose chafer, is a beetle, 20 mm long, that has metallic green coloration with a distinct V shaped scutellum, the small triangular area between the wing cases just below the thorax, and having several other irregular small...
", the other being the Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an Cetonia aurata. M. subspinosus occurs from Eastern Canada
Eastern Canada
Eastern Canada is generally considered to be the region of Canada east of Manitoba, consisting of the following provinces:* New Brunswick* Newfoundland and Labrador* Nova Scotia* Ontario* Prince Edward Island* Quebec...
to Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
and is considered a pest of many crops and flowers. It is given its common name of rose chafer because it eats the leaves of roses, although it also feeds on many other plants.
Identification
The rose chafer has a yellowish-tan coloured body that is about 8–13 mm (0.31496062992126–0.511811023622047 in) in length, with wings that do not completely cover the abdomen. The beetle has six long, spiny, reddish-brown legs that gradually become darker towards the end of the appendage. It has two short lamellate antennae that end in a club of flat plates and it has chewing mouthparts. Rose chafers are covered in dull yellow hairs which give the body its characteristic colour, however with age and with normal activity the hairs are worn off the head and thorax revealing a black colour. It is thus possible to distinguish between older and younger beetles, as older beetles will have fewer hairs and thus be darker in colour. Females tend to lose more hairs, especially on the thorax due to the mating process, and can also appear darker in colour. Females also tend to be more robust than the male. The eggs of the rose chafer are about 1 mm in length and are oval, white and shiny. The larvae are white C-shaped grubs that when mature develop a brown head capsule and three distinct pairs of legs. The pupae are yellowish-brown in colour and are about 15 mm in length.Life cycle
As a member of the order Coleoptera, the rose chafer undergoes complete metamorphosisHolometabolism
Holometabolism, also called complete metamorphism, is a term applied to insect groups to describe the specific kind of insect development which includes four life stages - as an embryo or egg, a larva, a pupa and an imago or adult. Holometabolism is a monophyletic trait that all insects in the...
during its development. In late May, white-bodied larvae, about 18 millimetre (0.708661417322835 in) long, pupate after having overwintered deep in the soil. Once they have emerged from their pupal case, adults live for 3-6 weeks, during which time they will feed on plant material and mate. Their eggs are laid in sandy soils, 15 centimetres (6 in) deep, and hatch in 1-3 weeks. This new generation of larvae will feed on the roots of grasses, weeds, and some ornamental garden plants during the rest of the summer, before they burrow deep in the soil to overwinter; these larvae will emerge as adults in the following year.
Behaviour
After adult rose chafers emerge in late May to mid-June, they aggregate on leaves, buds, flowers, and fruit, in order to feed and mate. By chewing on plant tissues, the rose chafer induces the release of volatile compounds from the plant. Using their antennaeAntenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
, rose chafers can detect the plant compounds in the air and orient themselves in the direction of the feeding conspecific, leading to an aggregation of the beetles. Male rose chafers also orient themselves preferentially toward virgin females as opposed to mated females, though it is unknown whether they are detecting pheromone
Pheromone
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting outside the body of the secreting individual to impact the behavior of the receiving individual...
s released by virgin females, or the release of plant volatiles induced by the feeding virgin females.