5.1. Life cycle of T. mercedesae on A. mellifera

As mentioned, to begin their reproduction, mated female mites enter A. mellifera worker or drone brood cells that are in the process of being capped (Burgett et al., 1983; Ritter and Schneider-Ritter, 1986). There is no marked difference in the type of cell type that female mites choose to reproduce in. However, much variation has been reported in the timing of different events during the reproduction phase. After entering a cell a single female mite lays from 1-4 eggs (but typically 3-4) about 1 day apart. A comparison of the time in hours after cell capping that the first egg, larva, protonymph, deutonymph, and young adult mite appear in a cell, as reported by different authors, is shown in Table 3.

At the end of the reproduction phase, the mother mite and her offspring exit the cell when the developing bee chews its way out of the cell through the wax capping. They then enter a brief phoretic phase, in which they move about the comb, probably mate (as recently emerged male and female mites have been observed mating in glass test tubes (Woyke, 1994)) and spend time on adult bees, before they commence a new reproduction phase. The phoretic phase of T. mercedesae mites is much shorter than that of Varroa mites, and may be as short as 1-2 days. This means that T. mercedesae mites have quicker reproductive cycles than Varroa mites and hence their population buildup within a bee colony is much faster than that of Varroa mites, said by a UK Government source to be in the order of about 25:1 in favour of Tropilaelaps (DEFRA, 2005). A diagram that summarizes data on the life cycle of T. mercedesae on A. mellifera in New Guinea, reported by Saleu (1994), is shown in Fig. 9.

Table 3.  Comparison of time (in hours) after bee brood cell capping of the first appearance of different developmental stages of T. mercedesae, as reported in 4 different studies: Saleu, 1994 (New Guinea); Kiprasert, 1984 (Thailand); Woyke 1984, 1985a (Afghanistan and Vietnam); Kumar et al., 1993 (India). The numbers in brackets represent honey bee brood development time in days.

Mite
development
Stage                   

 

 Study 1         

 

 Study 2         

 

 Study 3         

 

 Study 4         

Egg:

72

(10-11)

 

96

(12)

 

24-48

(9-10)

 

96

(12)

 

Larva:

96

(11-12)

 

96

(12)

 

24-48

(9-10)

 

96

(12)

 

Protonymph:

96

(11-12)

 

192

(16)

 

72-96

(11-12)

 

192

(16)

 

Deutonymph:

168

(14-15)

 

216

(17)

 

120

(13)

 

192

(16)

 

Young Adult:

216

(16-17)

312

(22)

192

(16)

298

20)

 

 

 


 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 9. Life cycle of T. mercedesae on A. mellifera. Diagram was constructed from data reported by Saleu (1994). Photo: Denis Anderson.

figure09