Bombus magnus

Bombus magnus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Apidae
Genus:	†Bombus
Species:	† B. magnus
Binomial name
Bombus magnus Vogt, 1911

Bombus magnus is a member of the bee genus, which was first described as a single species by Vogt in 1911.

While B. magnus has only been recently described in Ireland, Kosior and colleagues^[1] examined historical data showing that B. magnus was described in Cracow, Poland as early as 1973. It can be inferred that B. magnus has migrated northward due to environmental pressures or because the identification of species criteria at the time caused B. magnus to be classified as another member of the Subgenus Bombus.

Gaston^[2] provides figures ranging form 40,000 to 600,000 species of Hymenopterans Hymenoptera alone! The data he presented in 1991 estimated that the number of fully described insects from the Apoidae Famliy is 20,000.

Identification

Morphology

A diagnostic feature of species described by Richerson et al.^[3] is the sensillum placodeum on the antennae. With respect to the sensillum, if there is a different morphology, then it is likely that these two or more species are different from one another based on Phylogenetic Speciation. Another problem is discerning a difference between species. “Cryptic species are those that satisfy an accepted concept of species, but which are closely similar or identical in morphology.”^[4] Many times, a specimen will be classified a member of a species based on its similarities to another member of that species. In the case of B. magnus, several taxonomists have argued that it is part of a long-ignored species, or really part of another species and was mis-identified; however, speculation is that species belonging to the subgenus Bombus are a ‘species complex’ or a ‘sibling species'.

Arbuckle and colleagues^[5] were using ABIS (Automated Bee Identification System) software and assessed the accuracy at which this software identified different species of the genus Bombus. In short, the software examined the veination of the wings, compared them to known and scientifically described species, and conducted a non-linear statistical method (such as SVM and KDA) as the final stage. Their findings indicated that B. lucorum, B. terrestris, B. cryptarum, and B. magnus are very similar and difficult to identify, even by experts.

Another method of species identification is to compare the labial gland secretions across other taxa and examine them for any chemical differences. Bertsch and Schweer^[6] examined bees from several species in the Genus Bombus, among them was Bombus magnus. The goal was to establish a 95% similarity in male labial gland secretions among the species recovered; if they could do so, it was inferred that there wasn’t enough difference to accurately establish a difference in species. However, while members of B. magnus and others were determined to have the same chemical, ethyl dodecanoate, a 90-95% accuracy couldn’t be established. It seems likely that B. magnus is a member of the B. cryptarum species as either a subspecies or not.

Genetics

With the advent of genetic sequencing, it is easier to connect a specimen to an existing database to determine the species. Pons^[7] and colleagues examined the accuracy of this method while examining undescribed Coleopterans, genus Rivacindela, in Australia. As mentioned with Arbuckle et al., morphology alone is very difficult (but not impossible) to accurately identify a species based; conversely, it is very difficult to establish a different species strictly based on genetics. Carolan et al.^[8] investigated DNA barcoding in the B. lucorum complex to determine if DNA barcoding is accurate. They have concluded that due to many intraspecific variance of genetic sequences, it is extremely difficult to tell the species of the B. lucorum complex apart from one another. Another study that also shows this level of variance is by Bucankova and colleagues.^[9] They collected members of the B. lucorum complex, for laboratory rearing, and found that: “…molecular analysis even assigned to B. cryptarum one specimen determined morphologically as B. aff. magnus.” (2011). In addition, Williams and colleagues^[4] collected samples of the current species of the Subgenus Bombus and did attribute that members of the B. lucorum complex have genetic similarities; however, there are diagnostic nucleotide changes that exist amongst B. lucorum, B. terrestris, B. cryptarum, and B. magnus that allow it to be classified as a separate species – despite morphological similarities. Furthermore, a study by Murray and colleagues^[10] did find four unique genetic banding patterns amongst the lucorum complex using DNA RFLP. That is to say, they found four unique haplotypes to each species, which can used to identify each species accurately using genetics.

Habitat

It is not uncommon for Bumblebees to become introduced into a novel (non-natural) environment. Matsumura, Yokoyama, and Washitani^[11] observed the introduced species Bombus terrestris is successful in competing with native bees (in this case: Bombus hypocrita sapporoensis) for pollen. As such, the widespread occurrence of B. terrestris is not a surprising fact.

Decline

Entire populations of Bombus species are steadily declining as the years go by. A number of efforts are being undertaken by the ICUN. This population collapse has been named: Colony Collapse Disorder. It is also believed that due to agricultural use of land, plants that Bees have adapted to are disappearing, as described in a study by Goulson and colleagues^[12]

See also

• List of bees of Great Britain

References