Honeybee worker larvae perceive queen pheromones in their food

Abstract

-Honeybee workers develop from fertilised eggs, but those reared in a queenless colony develop into 'rebel' workers, which are more queen-like than typical workers. Rebels develop after an old queen leaves with a swarm and before a new queen hatches. We hypothesised that larval food lacking queen mandibular pheromones trigger the rebel phenotype. Larvae reared under queenright or queenless conditions were additionally fed with water or a drop of macerated queen mandibular glands. After following development of the bees and subjecting them to dissection, we found that those reared with a queen or fed the macerated glands under queenless conditions developed into typical workers. Only those workers reared without a queen and without macerated glands added to their food developed into rebels; these rebels had more ovarioles, smaller hypopharyngeal glands, and larger mandibular and Dufour's glands than did typical workers. This is the first evidence that larval perception of the presence or absence of queen pheromones causes an alternative development strategy.Apis mellifera / honeybee / queen pheromones / queen recognition / rebel workers

Honeybee rebel workers preferentially respond to high concentrations of sucrose

“…All colonies were treated in the same way, and the experimental design was previously described by Woyciechowski and Kuszewska (2012) as well as in other papers (i.a. Kuszewska et al 2017Kuszewska et al , 2018bWoyciechowski et al 2017). At the beginning of the experiment, the queen was restricted to two experimental frames to produce eggs of a similar age (day 0).…”

“…These rebel workers differ anatomically from normal individuals as follows: they have more ovarioles in the ovary, larger mandibular and Dufour's glands and underd e v e l o p e d h y p o p h a r y n g e a l g l a n d s (Woyciechowski and Kuszewska 2012; Kuszewska and Woyciechowski 2015). The development of rebel workers is directly connected with the absence of the queen in the nest (Woyciechowski and Kuszewska 2012) and absence queen's mandibular gland pheromone (Woyciechowski et al 2017) during the unsealed larva stage of workers, which naturally occurs after swarming which is the only natural method of colony multiplication (Winston 1987). Larvae orphaned by four or more days change their life strategy and develop into rebel workers (Kuszewska and Woyciechowski 2015).…”

Do rebel workers in the honeybee Apis mellifera avoid worker policing?

“…Rebel workers develop immediately after swarming, which is the only natural means of colony multiplication. The proximate factor suggested to affect rebel sub-caste development is the absence of a queen or, more precisely, absence of the queen mandibular pheromone in larval food delivered by the workers (Woyciechowski et al 2017), whereas the decreased relatedness between the old queen's workers and the new queen's offspring occurring after swarming seems to be the ultimate factor underlying the shift in resource reallocation to reproductive tissue in rebels (Woyciechowski and Kuszewska 2012). Compared with normal workers, rebels exhibit significantly more ovarioles in their ovaries, more developed mandibular and Dufour's glands, and smaller hypopharyngeal glands (Woyciechowski and Kuszewska 2012;Kuszewska and Woyciechowski 2015), which produce brood food (Huang and Otis 1989).…”

Rebel honeybee workers have a tendency to become intraspecific reproductive parasites

“…These anatomical differences show that rebel workers are more engaged than normal workers in laying their own male‐determined eggs. The proximate factor that influences rebel caste development is the absence of a queen or, more precisely, the lack of a queen's mandibular gland pheromones (Woyciechowski, Kuszewska, Pitorak, & Kierat, ) during the larval feeding period (unsealed larvae). If they remain in a queenless or a queenright colony during their adult lifetimes, these rebel workers display active ovaries (Woyciechowski & Kuszewska, ) and have a higher number of male offspring than normal workers (Kuszewska, Wącławska, & Woyciechowski, ).…”