I might be mistaken but I thought that many queen imports were delayed this year due to bad weather in Greece and Continental Europe.
This article has good background information on the timing and frequency of mating flights.
http://scholar.lib.vt.edu/theses/available/etd-08162007-092313/unrestricted/lmburley.pdf
The first task of a newly emerged queen is to seek and destroy potential rivals
either existing queens or queens in cells awaiting emergence (Laidlaw and Page 1997,
Caron 1999). Virgin queens are smaller than mated queens and tend to be more active
and flighty. Virgin queens are fed primarily honey until after mating; honey gives virgins
strength and energy for mating flights (Laidlaw and Page 1997). Mating of the queen
takes place with multiple drones outside of the hive. Three to 5 days after emergence a
queen will take orientation flights to become familiar with the location of her colony;
mating can sometimes occur on these flights (Caron 1999). Typically, virgins will make
one or more mating flights five to fourteen days after emergence from her cell (Roberts
1944, Woyke 1964, Mackensen and Tucker 1970, Harbo 1985, Caron 1999). If the
weather is unfavorable for multiple weeks, and a virgin cannot leave the hive to mate, or
she is unsuccessful during mating flights, then she may start laying unfertilized eggs.
Queens that only lay unfertilized eggs are known as “drone layers” and will not leave the
hive again for mating purposes (Laidlaw and Page 1997).
The number of drones with which a queen will mate varies from queen to queen.
It is currently estimated that a queen will mate with between 6 and 24 drones (Woyke
1962, Winston 1991, Neumann et al. 1999) mating with 5 to 10 in rapid succession
(Koeniger 1990b). The number of mating flights a queen takes also varies. It is thought
that a queen will make repeated mating flights due to a lack of sperm received and stored
on the first flight (Roberts 1944, Woyke 1964). Through his research Taber (1954) found
virgin queens mate on average 6.5 times over multiple mating flights. Virgin queens
allowed only one mating flight had significantly lower sperm (3.27 million) contained in
the spermatheca than queens that were able to freely mate (5.73 million) signifying
multiple mating flights. Results of progeny of queens allowed to mate once clearly
indicated that queens mated with more than one drone on a mating flight based on allele
frequencies (Taber 1954). Woyke (1964) observed that queens will repeat mating flights
up to three times with the average number of stored sperm increasing with each flight.
Two mating flights on the same day can occur but is not likely. Only 6.8% of mated
queens flew again on the same day to mate further; most of the queens were found to
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mate again on succeeding days. If a queen does conduct a second mating flight on the
same day, the duration of the second flight is dependent on the time interval between the
first and second flight (Woyke 1962). The longer the time interval between the first and
second flights, the shorter the second flight, and the less likely the queen was to mate
successfully on it.
The duration of mating flights can vary depending on the success of the flight
and season of the year. Flights when queens successfully mate last longer than
unsuccessful mating flights. Non-successful mating flights average 11 minutes in
comparison to successful mating flights that average 14.4 minutes with some flights
lasting as long as 31minutes (Roberts 1944). Woyke (1962) observed a slightly higher
average of 21 minutes for a successful mating flight with a second mating flight on the
same day lasting 20 minutes. A time interval between two successful mating flights is
much shorter (47minutes) than the interval between the first successful mating flight and
an unsuccessful mating flight (77 minutes) (Woyke 1962). Mating flights tend to be
longer in early spring and then shorten in the summer when the temperatures are warmer
and drones are more abundant (Roberts 1944, Laidlaw and Page 1997). Roberts (1944)
for example, showed that duration of mating flights decreased from 19.3 minutes in April
to 11.9 minutes in June.
