Assessment: Called to look at a hive that had experienced a sudden (less than one week) drop in population and an increase in dead bees accompanied by “sawdust” like material.
Location: Swansea, SC Weather: Mid 60’s overcast. Light wind.
Hive is a 10 frame Langstroth, three hive bodies tall (two deeps, one medium).
By history, this is a new hive installed this season from a package (H&R). Hive has been doing well until a couple days ago. Owner inspected hive last week and reports “full boxes of bees”. Became concerned this weekend with increase in dead bees on ground in front of hive and “sawdust” like material in front.
On arrival I noticed an open feeder located a couple feet to the side of the hive. Noticing more bees coming and going at the feeder than the front entrance of the hive I watched and saw bees coming to the feeder and on departing going elsewhere . Owner reports neighbor has multiple bee hives.
The hive had little activity at the entrance reducer which was set on about a two bee width setting. No fighting.
Owner showed me “sawdust” like material. Appeared to be animal scat largely composed of bee parts.
Hive opened and no bees noted on opening. Top medium all frames filled with capped honey.
Middle box deep had a cluster of bees approximately 200. No queen observed. Three emergency queen cells observed but these were away from cluster but on same frames. Appeared queenless. Approximately 20 capped brood cells. No open brood noted.
Bottom deep partially filled with open nectar. Apparently cured as passed the “shake” test.
Screened bottom board had about 20-30 dead bees.
Sticky board was under the SBB. Had been in place for unknown period of time. Had notable number of mites, a few SHB, minimal wax particles.
While I generally discourage viewing individual bees as an assessment of Varroa load, I did observe the bees on the top of the small cluster. Approximately 25 bees were on the top bars of the middle box gathered together at top of cluster. I counted 4 or 5 mites on the top surface of the bees’ thoraxes and abdomens.
Removal of pupae from capped brood. No mites observed. Pupae had been dead several days and starting to dehydrate and decompose.
Analysis of Assessment:
Upon seeing bees other than the bees from the owner’s hive I initially suspected an abscond due to robbing pressure. However I ruled this out after seeing 1) no fighting or increased activity at the front entrance of the hive; 2) No torn cappings or wax on SBB; 3) hive stores intact.
The scat like droppings containing bee parts led me to suspect harassment from a raccoon or other small animal. However, it is my understanding that raccoons will scratch on the hive box or entrance at night to get bees to come out so they may eat them. However, I saw no scratches on the box or landing board. Additionally, I understand that raising the hive off the ground is a method of discouraging raccoons because it causes them to expose their undersides which the bees sting. This hive was raised further discounting the raccoon harassment leading to an abscond. The scat remains a mystery however, it is possible the scat was from another animal, perhaps a snake regularly eating dead or dying bees off the ground in front of the hive. I have lizards at my home yard that eat the dying bees on the ground and are a benefit to yard hygiene.
Owner reports increased yellow jacket activity. Not noted on inspection. We have had a couple recent freezes so that may account for lack of activity today. It is, however, noted as another pest pressure on this hive.
Varroa on bees. Counting 5 per 20 bees is a 25% Varroa load and well beyond economic threshold for treatment. It is generally considered that a functioning hive cannot withstand a mite population greater than 3000 total and is considered doomed. I suspect this hive had a mite load sufficient to cause death / absconding.
Remove capped honey
Safely store comb for next season
Provide educational tips
Box with small cluster placed on hive stand. Owner advised that they are hopelessly queenless and doomed. However, as the owner had no other hive to work with and she did not wish to shake them out on the ground. Owner advised to recover and save comb after the bees die.
The hive bodies containing capped honey were removed for processing.
Combs with extracted honey will be placed outside for neighbor’s bees to clean up for 24 hours prior to being stored. Owner instructed in proper comb storage options.
Restart hive(s) in spring with packages placed on drawn comb.
Do not open feed in close proximity to hive. Feeding close introduces your hive to the neighbor’s hive and during times of dearth weaker hives are identified. I do not think this was an issue in this instance however it can lead to a “stressor” on the hive to defend its stores. Additionally, open feeding promotes viral disease transmission via contact with other, possibly infected, colonies.
Treat for Varroa earlier in the year. Given that we now know there are multiple hives located in close proximity to the owner’s bee yard, I recommend treatments at the close of the nectar flow, and again in early fall. An assessment of Varroa counts in the spring as well would be advised.
Perform the final “deep” inspection a bit earlier in the fall. Do final total inspection in early fall to ensure the queen is where you want her (lower boxes) and to assess stores prior to any fall feeding. After early fall inspection let them get their house in order. Remember, while we are trying to help the bees, we are not perceived by them as helping. To them, we are another pest in their hive.