# MFCC Selection by LASSO for Honey Bee Classification
## 1 Introduction
### Drones' Flights  
Drones do not survive the winter since they die after mating with a queen, and the remaining drones that do not mate are expelled from their colony in the fall to save stored food. The drones die off because of the lack of food and cold exposure after being forcefully removed from their hive. Young drones are raised the following spring. The drone brood is easy to spot because it is closed in an arched way on the top and is larger than the worker brood.  
The drones occur in their colony seasonally with a peak in late spring. Their main task is to fly to drone congregation areas [8; 9; 10], where they mate with newly emerged queens. To be able to fly to such distant locations, drones prepare by performing orientation flights and strengthening the flying muscles. The observation of marked individual drones [16] indicates that they are actively flying out the hive only in two periods corresponding to the following:  
* **Orientation flights--**short flights of about 15 min performed by 6-9-day-old drones [16];
* **Mating flights--**longer flights of about 30 min of older drones when they visit drone congregation areas. For example, in the study [16], the observed drones performed mating flights in the spring season from the age of 21 days to the end of their life. In the summer season, the same study registered mating flights of drones from the age of 13 days, but their life span was considerably shorter, with a maximum of 21 days.  
In the first period, the immature drones (6-9 days old) perform orientation flights, which are followed by several days of resting inside the hive.  
Drones achieve sexual maturity after 10-12 days from their emerging. The second period of the highest activity of drones is when they form congregation areas [10], where they gather in large numbers: several hundreds to 30,000 drones from potentially 240 different colonies in one place. Such a DCA usually takes place 5-40 m above ground [17] and can be 30-200 m long across. Most daily flights of sexually mature drones to drone congregation areas occur between 14:00 and 18:00, with a marked peak of activity at 16:00 [18]. The daily peak in drone activity at around 16:00 remains constant and seems to be less sensitive to changes in weather conditions compared to the worker bees' peak. Drones commonly move between congregation areas during a single flight [9].  
The study [16], based on an optical bee counter at the entrance of a hive counting the number of marked individual drones that returned to the hive, shows \"a period of very low activity\" between the orientation and mating flights. On most of the days, the number of worker bees exiting their hive exceeded the number of exiting drones, but on some specific days, the afternoon peak activity of drones (16:00) significantly preceded the workers peak.  
Various studies [15; 19; 20; 21] show that the **drone population peaks around the time of the swarming peak**. It is a consequence of the peak of drones rearing a little over a month before swarming. It is not a coincidence considering that the primary goal of the drones is to mate with new queens. It takes approximately 35 days from the laying of the unfertil egg in the drone cell to develop a fully mature drone [22].  
On average, the young queens mate with 12 drones [7] and store the spermatozoa in their spermatheca for future egg fertilization. The nuptial flights can occur over a period of several days, during which young queens take 1-6 flights per day [16] to visit DCAs.