Effects of Infection on Honey Bee Population Dynamics: A Model

Abstract

We propose a model that combines the dynamics of the spread of disease within a bee colony with the underlying demographic dynamics of the colony to determine the ultimate fate of the colony under different scenarios. The model suggests that key factors in the survival or collapse of a honey bee colony in the face of an infection are the rate of transmission of the infection and the disease-induced death rate. An increase in the disease-induced death rate, which can be thought of as an increase in the severity of the disease, may actually help the colony overcome the disease and survive through winter. By contrast, an increase in the transmission rate, which means that bees are being infected at an earlier age, has a drastic deleterious effect. Another important finding relates to the timing of infection in relation to the onset of winter, indicating that in a time interval of approximately 20 days before the onset of winter the colony is most affected by the onset of infection. The results suggest further that the age of recruitment of hive bees to foraging duties is a good early marker for the survival or collapse of a honey bee colony in the face of infection, which is consistent with experimental evidence but the model provides insight into the underlying mechanisms. The most important result of the study is a clear distinction between an exposure of the honey bee colony to an environmental hazard such as pesticides or insecticides, or an exposure to an infectious disease. The results indicate unequivocally that in the scenarios that we have examined, and perhaps more generally, an infectious disease is far more hazardous to the survival of a bee colony than an environmental hazard that causes an equal death rate in foraging bees.

Risk factors associated with honey bee colony loss in apiaries in Galicia, NW Spain

“…This result concords with and extends the earlier findings in this country . While there has been debate regarding the role N. ceranae plays in CL, recent research has reached consensus that under certain conditions N. ceranae causes collapse to honey bee colonies (Betti et al, 2014;Bekele et al, 2015;Cavigli et al, 2016).…”

Age structure is critical to the population dynamics and survival of honeybee colonies

“…Earlier versions of this model were introduced by Khoury et al in 2011 and 2013 [11,12] and were developed further in 2014 [13]. Analytical details of the model, including local and global stability of the disease-free equilibrium as well as a derivation of the basic reproduction number, R 0 , are presented in [14].…”

“…Such hazards may cause injury or death to foraging bees, forcing surviving bees to begin foraging prematurely which will then disrupt the dynamics of the colony, ultimately leading to colony collapse [10–12]. Further research has focused on the effects of parasitism and disease [13–18], for example, the effects of Varroa destructor on honeybee colony dynamics [15–18], the effects of the microsporidian parasite Nosema ceranae [19] and the effects of communicable infections more generally [13]. …”

“…[28] explored the interplay between environmental hazards and the subsequent susceptibility to Nosema ceranae . In previous work [13], we showed that the fate of a honeybee colony in the presence of disease is dependent on seasonality, particularly the onset of winter.…”

On the Effects of Artificial Feeding on Bee Colony Dynamics: A Mathematical Model

“…In spite of their relative mathematical simplicity, these models are more appropriate to analyze general factors that may affect bee population dynamics and lend themselves better to hypothesis testing [15]. This is the case of the framework proposed by Khoury et al [16, 17], which describes a colony population dynamics and has been used as a basis for studies by Russel et al [18], Betti et al [19], and Perry et al [20]. …”