Reproduction

 Vespa mandarinia is a eusocial colony forming insect and like any colony structure has queens and mainly female workers. Only at certain times are males produced, and once they are ready they later leave the nest to inseminate queens from other nests, who are raised and leave in the same timeframe. Generally in the Asian giant hornet it appears that the queens are inseminated by just one foreign male rather than multiple males. It also appears as if the workers police their egg production, ensuring that for the vast majority of cases all males are produced by the queen, which seems to result in a low to non-existent amount of haploid males (Takahashi and Akimoto 2004). As with most members of this group, the Asian giant hornet constructs a nest for the colony and the young to live in. However, unlike some members of Vespa the coverings are rough and not perfectly constructed, lack a complete covering over the nest, and have the lowest combs exposed. Additionally they do not build their combs from a central point but rather build them from several different points, fusing them as time goes on and ignoring the combs at the top of the nest to disrepair. This is another marked contrast to relatives like Vespa mongolica and Vespa crabro, which strengthen these zones to increase stability of the nests other combs. A V. crabo is shown here for comparison, and its diminutive size can also indicate how a weakened colony could be overtaken by V. mandarinia.

                 
Surprisingly despite its large size, the Asian giant hornet is outranked in the amount of cells it produces by V.mongolica by a wide margin. This leads to the feeling that these nests are less complex than other Vespa family members, and one of the papers describes this as almost “primitive”, though he believes that it is a possible result of its subterranean lifestyle. Additionally the larvae are first laid in early July once a fertilized queen finds a proper nesting site. The queen builds the first group of combs and rears the workers she needs to build the nest, which are produced until mid-September when males and new queens begin to be produced (Matsuura and Sakagami 1973). These larvae have the lowest cranial width to mouth parts width ratio of the observed Vespa, as well as a lack of a mid-cranial sulcus just above the clypeus-or a groove in the middle of the insects face above an individual segment of the face directly above the mandibles. The larvae also have a specialized head shape different from other Vespa, separating it further from other closely related wasp species that share the same above traits. However a trait it shares with all members of the Vespa family is that when hungry, the mature larvae will scrape the sides of their comb with their mandibles, and were shown to always accept food, as opposed to those larvae who did not scrape the comb walls (Seiki 1976). V. mandarinia larvae, like all other members of the Vespa family and many other members of the Hymenoptera Order, produce silk around themselves to further cocoon themselves in their combs. Their silk proteins are most similar to Vespa ducalis, as both contain a special protein-dubbed 6-that none of the other Vespa tested contain, possibly due to closer relatedness than other members tested (Kameda and Kojima et al. 2008). A V. ducalis is shown here at the patch, and while it is similarly colored, it can be seen to be much smaller as compared to the V. mandarinia, shown in the third image on the adaptation page feeding at the same patch.

                   
After mid-September the males and new queens start leaving the nest, and they will never return. Uniquely for the Asian giant hornet, males will visit other nests and wait at the entrances for the new queens, attempting to mate with them as they depart. The queens will find somewhere to hibernate regardless of whether or not they mate, sometimes even forcing the male off and continuing onwards, to find some sanctuary until the next season (Matsuura and Sakagami 1973).

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