The 2011 ASHS Annual Conference

Insect visitors were identified and pollen loads examined for seven wild stands of Vaccinium uliginosum, Alaska bog blueberry, the most important wild-collected fruit in Alaska. Visitors included 212 insects, 133 of which carried Vaccinium spp. pollen with 21 of individuals holding more than 500 pollen tetrads. The insects with high pollen loads were primarily Bombus species (B. frigidus, B. centralis, B. perplexus, B. jonellus, B. mixtus, B. balteatus, and B. sylvicola), and one Apis mellifera (honey bee) specimen. Two flower flies or hover flies (Syrphidae) contained more than 100 tetrads.  The top five pollinator species differed between upland and lowland sites, though B. frigidus and B. jonellus occurred at both. Apis mellifera was collected only at lowland sites. Insect activity occurred primarily between 8:00 a.m.(08:00) and midnight (24:00). After 8:00 p.m.(20:00) the honey bee visitations ceased, while Bombus spp. visitations continued until about midnight. Fruit production occurred in plants enclosed in insect exclusion screens but at significantly lower levels than unprotected plants. Attempts to attract bumble bees using the blue colored cap from blue vane traps (Japanese beetle traps) or blue flagging did not increase fruit set or size. Under greenhouse conditions (av daily temp 15C,  daylight supplemented with HID sodium, 240 µM m^-2 s^-1, 16h photoperiod), anthesis lasted about three weeks with peak bloom occuring around the day 12-13.  Fully opened flowers that lasted 4 - 5 days had receptive stigmas, indicated by a creamy exhudate, for an average of 3.4 days.  Floral nectar is produced, with an average nectar standing crop of 0.2103 µL + 0.1128µL  one day after the beginning of anthesis. No correlation existed between maximum daily temperature and nectar production but was negatively correlated with relative humidity (av 28.4%). Pollen was released from flowers by vibration over a wide range of frequencies (150-850 Hz). Although flowers showed a peak resonace frequency of  250-300 Hz, pollen was not released in higher quantities at this frequency, nor was there a peak at any known insect vibrational frequency for buzz pollination.