Contents
An Unsuccessful Try to Create Robbing
Subject Observations of the Guards Behind Robbing Screens
How Colonies Guard Themselves in opposition to International Bees
The Habits of Guard Bees
My Conclusions
Subsequent Month
Acknowledgements
Citations and Notes
Robbing Screens Half 8:
Do They Work in Live performance with the Guard Bees?
Randy Oliver
ScientificBeekeeping.com
First Revealed in ABJ February 2025
After we monitor the higher openings of the robbing screens that we’ve examined, we will’t assist however discover that there are seldom any guard bees manning these portals to verify the IDs of bees trying to realize entry!
I can’t imagine that I’m eight articles into this sequence! Enable me to start with an admission: till researching this topic, I’d by no means used a robbing display. I started this analysis solely to reply a query posed to me: Are robbing screens efficient at lowering mite immigration? The reply seems to be “no,” however as is widespread in scientific analysis, one query results in one other, and that to yet one more, and maybe to discoveries that you simply by no means dreamed of.
AN UNSUCCESSFUL ATTEMPT TO CREATE ROBBING
By this time in our experimentation with robbing screens, it was autumn of our second 12 months, and robbing stress in our dwelling yard was robust. It occurred to me that this was our likelihood to check whether or not robbing screens may really forestall the robbing of weak colonies from occurring. So we ran a small preliminary experiment.
We had a few rows of late-season nucs out there in my dwelling yard, so we transferred 10 of them (at their unique areas) into the facilities of single deeps (equalizing them to 4-5 combs of bees), including drawn comb and capped honey to both aspect to fill all ten body positions (thus creating 10 weak colonies having a restricted variety of bees to protect their fascinating honey). We randomly put in three varieties of robbing screens (2 of every sort, plus 4 unscreened Controls), and gave the colonies just a few days to get used to their new containers and robbing screens (Determine 1). Throughout that point, we open fed anise-scented sugar syrup just a few instances a day between the rows of the check hives. At every feeding, the syrup trays have been mobbed by foragers (presumably from one other 50 hives sitting close by), and investigating bees have been interested in the alluring scent of anise wherever property.
Fig.1 Our try to check whether or not robbing screens may forestall weak colonies from being robbed out. Corrine and Rose helped me monitor the motion on the hive entrances. Within the foreground is jug of the scented syrup that we used to stimulate robbing stress.
As soon as the intentionally-weak check hives have been settled down, we let the open feeders go dry every day, and elevated the robbing stress on the check hives by offering them with scented sugar syrup by way of their high feeding holes (generally simply squirting it in), in order that they might be exhausting the odor of the bait syrup out their entrances. This instantly created robust robbing stress, and we may simply observe defensive habits and preventing on the Management hive entrances, however not on the screened hives (though some had lifeless bees on the bottom in entrance of them.
RESULTS: To our nice disappointment, not a single hive bought overwhelmed by robbers — whether or not they had a robbing display on or not. We repeated the feeding and baiting of the check hives for a few weeks, however regardless of their small clusters and aromatic items inside, danged if we may induce the robbing out of a single one. 🙁
Though I’m fairly aware of watching the high-mite colonies that I carry dwelling for experimental functions get robbed out of their closing phases of collapse, the above end result was according to what I’ve noticed through the years. In my location, it usually takes solely a handful of guard bees to stop robbers from having access to even a weak hive containing capped honey (versus these containing open nectar).
A earlier statement: It occurred to me that final 12 months I had tried time and again to take an illustrative picture of bees guarding the higher opening of the stainless-steel robbing screens that was testing on the time. However I used to be by no means capable of catch a guard doing so! So I made a decision to start out focusing my consideration upon the guard bees.
FIELD OBSERVATIONS OF THE GUARDS BEHIND ROBBING SCREENS
Our earlier analysis confirmed that after we fitted scent-baited empty hives with robbing screens, some potential robbers finally discovered their method in. So why did these weak check hives not get robbed out? We may clearly observe the motion of the guard bees on the entrances of the unscreened Management hives, however was that additionally occurring on the openings of the robbing screens?
So day after day, and in several areas and hives, we carefully watched (and filmed) the habits of the bees on the openings of the various kinds of robbing screens, in addition to on the entrances of Management hives subsequent door.
RESULTS: Opposite to the apparent guarding habits on the entrances of unprotected Management hives, what my helpers and I noticed on the high openings of the three varieties of robbing screens, is that solely sometimes was there any guarding habits evident at these high openings, and even monitoring of incoming bees by any guards! (Determine 2).
Fig. 2 Word the shortage of outward-facing guard bees at this higher opening. Though most of a colony’s foragers finally be taught to make use of the highest openings, it was uncommon for us to see the faces of any guards going through outward, or any head turning or different response to our waving fingers or a swinging lifeless bee lure. This strongly instructed that guard bees don’t acknowledge the highest opening of a robbing display as the doorway to their nest cavity.
The shortage of guarding habits on the openings of the robbing screens actually stunned us. To additional examine, I reduce plastic and stainless-steel guards to position black window display in entrance of each the highest opening and the decrease hive entrance, in order that we may observe whether or not incoming bees (both returning foragers or investigating “thieves”) have been ever checked by guards (Determine 3).
Fig. 3 After I put viewing screens in entrance of the highest openings, we’d solely sometimes observe a guard — however even they have been usually exterior the screens. Solely not often did we observe a guard intercepting any incoming international bee inside the highest opening. We laid on our bellies day after day when there was loads of robbing stress, and watched bee after bee enter the highest opening after which simply stroll right down to the decrease entrance with out ever being checked by a guard.
Sensible software: I believe that the shortage of guards on the high openings could also be because of the guards not recognizing that remote-from-the-cluster opening (with gentle coming in between it and the precise nest cavity entrance) because the place to take up their defensive place.I could also be making a dumb assumption, but it surely appears to me {that a} robbing display is likely to be much more efficient if it have been designed to work at the side of the colony’s guard bees, and encourage them to arrange an inspection station on the robbing display’s opening. So I dug into the literature to see what I may be taught in regards to the habits of guard bees, and particularly what cues set off them to “activate” and problem an incoming international bee.
HOW COLONIES GUARD THEMSELVES AGAINST FOREIGN BEES
There are any variety of critters that might like to gorge on the energy-rich honey saved in a hive, so honey bees have advanced efficient defenses in opposition to them. Just a few massive predators, akin to honey badgers, bears, and people, require {that a} colony shops its items in a robust bodily fortress, ideally excessive above the bottom. However most smaller predators or thieves are deterred by the bees’ painful sting. Others, akin to ants, are recognized by scent, and bitten.
However wherever that colony density is excessive, the bees should additionally shield their honey from theft by foragers from different hives, particularly when floral nectar sources dwindle. Hungry foragers will then examine any scent that they could affiliate with a sugary reward — particularly that of ripening nectar or inadequately guarded honey.
Sensible software: A colony’s innate and best protection in opposition to such potential nectar thieves are its guard bees! So a robbing display would probably carry out greatest if it was designed to work in live performance with the guard bees.
THE BEHAVIOR OF GUARD BEES
Within the typical development of “jobs” {that a} employee bee performs over the course of its life (“temporal polyethism”), some might act as guards for a day or so (simply previous to transitioning to foraging). Bees performing as guards are kinda like “seasonal temps” — a short lived standby drive that’s solely activated if wanted (the important thing phrase being “activated,” Determine 4).
Fig. 4 Activated guard bees assume a typical stance with their entrance legs raised, and their wings lifted for fast take-off, following any shifting object with their heads. The additionally problem, “sniff,” and tug at any bee that doesn’t appear “proper” to them.
As most beekeepers discover, when a colony is comparatively “undisturbed” and there’s a nectar stream on, few staff are inclined to behave as guards, and even these guards is probably not “activated” to any extent.
Sensible software: Any beekeeper who doesn’t put on gloves has discovered to maneuver easily, in order to not “activate” the guards. Any jerky motions of your fingers will provoke “warning bumps” from guards flying out to find out whether or not you’re a potential predator, or merely a tree department waving within the wind.
Youthful staff stay in darkness and keep away from gentle (being negatively phototactic), and don’t use their sense of sight (in the event you pull out a comb, the younger bees don’t even take a look at you). The one bees that take a look at you’re these performing as guards that day. Guard bees are extraordinarily observant of something that strikes, being looking out for a possible predator or thief.
A guard bee at a hive’s entrance should differentiate a possible thief from the hundreds of returning foragers (kinda like an FBI agent attempting to pick a terrorist in an airport foyer). The primary cue to alert them is visible discover of surprising motion, which they could then observe with an “id verify and patdown” (sniffing the bee in query for colony scent, and checking to see whether or not it tries to get away).
Curious foragers from one other hive (aka “honey thieves”) exhibit a typical “investigatory” strategy to a hive’s entrance whereas “sniffing” for the supply of the enticing scent. As an alternative of plunging straight into the doorway as do foragers returning dwelling, they wave forwards and backwards just a few inches in entrance of the hive (inspecting for hazard, and finding the place the odor is coming from). This investigative flight sample is acknowledged by the guards and places them on alert. When an investigating scout tentatively lands, it’s usually instantly challenged by a number of guards, and in contrast to a confused drifted bee, might attempt to escape.
Butler and Free revealed an enchanting paper in 1952 titled The behaviour of employee honeybees on the hive entrance [ ]. They describe how colonies usually enable drifted international bees who fly “straight in” to peacefully enter the hive — that’s, till a quantity have finished so, at which level the guard bees grow to be activated by the scent of “too many” intruders. The authors discovered that:
Excited guard bees watch the actions of bees flying overhead and approaching the hive, typically jerking spherical to take action, and make intentional actions to intercept any bee which they see alight close to them. Every guard tends to patrol a selected, circumscribed, space of the alighting-board, generally for an hour or extra, then to vanish both inside the hive or for a flight solely to reappear on guard as soon as extra on the similar a part of the alighting-board [Figure x]. Guard bees intercept and look at members of their very own colonies in addition to intruders from different colonies, and the guard bees themselves are sometimes in flip approached and examined by different guards of their very own colony.
Fig. 5 We additionally observe guards returning to their very same station after flight. After gluing metal discs on the backs of guard bees (recognized by them going through us with curiosity) on the highest bars, then releasing them to fly again to the hive, a big proportion of them then returned to renew guard obligation on the exact same high bars that they’d been plucked from a number of minutes earlier.
Butler and Free proceed (boldface mine): It was concluded from the outcomes of those experiments, that offered {that a} colony of bees has not been disturbed (and its members thus “alerted”), few, if any, guard bees can be current, and foragers from one other colony can enter the hive with out problem and even examination. If, nonetheless, the members of the identical colony have been “alerted,” a few of them begin to protect the doorway, and foragers from one other colony are, below these circumstances, liable to be intercepted and examined, though they nonetheless enter the hive with out hesitation or problem.
It’s clear from these information that the bobbing movement of a dead-bee lure on the hive entrance was ample to alert the experimental colonies, and that guard bees remained in proof for intervals various from 12-65 minutes, with a imply time of 28.5 minutes.
Once more, we’ve confirmed the above, additionally by utilizing a dangling dead-bee lure for additional investigation on many hives in several locales, with or with out robbing screens (Determine 6).
Fig. 6 We swung a suspended lifeless bee on a fish hook in entrance of hive entrances to gauge the response of the guards. It is a freeze body from a video — word how the guard bees have turned to observe the left-to-right movement of the swinging bee indicated by the yellow arrow (the high quality chief string doesn’t present ). Activated foragers will typically fly out to intercept and try and sting the bee lure.
A drifted bee usually walks proper into the international hive, but when stopped by guards, typically provides nectar — which is mostly refused. After such refusal the drifted bee my have interaction in “tongue stropping,” an regular habits that my placate the guards. But when the guards proceed to tug on the legs of the drifted bee, it goes solely passive and submissive (akin to “taking part in possum,” aka thanatosis). However (once more from Butler and Free):
When the guards succeeded in seizing a robber the latter invariably tried to interrupt away from them. Often an excited guard was seen to grab a member of her personal colony wherein case the latter adopted a submissive angle and was quickly launched. If a guard bee succeeded in getting a agency maintain of a robber she curled the tip of her stomach in the direction of the robber with none hesitation and tried to sting her. When this occurred the robber and guard bee ceaselessly lay on their sides, holding onto each other’s legs with their mandibles, and, in mutual makes an attempt to sting one another, buzzed spherical and spherical extraordinarily quick like a catherine-wheel. Normally in such instances one of many bees succeeded in stinging the opposite and, on being launched, the stung bee crawled away slowly, clearly significantly damage, and died inside 2-3 minutes or much less. Generally, nonetheless, the vanquished bee had such a good grip on the leg of the victor that the latter had nice problem in breaking away from the dying bee and even, in some instances, from the corpse. In each one of many many fights that have been seen to end result within the demise of a bee the victorious bee succeeded in withdrawing her sting from the physique of her sufferer extraordinarily shortly.
The steps of motion concerned in guarding are additionally described by Napier [ ]:
The mildest defensive habits is antennation, wherein guard bees rub their antennae on returning foragers and use scent cues to find out if the foragers are nestmates or non-nestmate intruders. The following habits is antennation with open mandibles, a menace habits. The following habits is biting, the place guards chew the legs, antennae, or stomach of forager bees. Stomach flexion is the subsequent most extreme habits, the place a guard grabs the forager and flexes her stomach with out extruding her stinger. Stinging is essentially the most extreme of the guard behaviors, wherein the stinger is extruded in an try puncture the cuticle of the opposite bee. See Determine 7.
Fig. 7 Guards actively antennating and biting an intruder. One guard is flexing its stomach in preparation for stinging (word the shininess of the bee being attacked, suggesting that it’s been beforehand engaged in robbing).
MY CONCLUSIONS
For greatest performance, an anti-robbing system would:
(1) Have a small entrance opening the place guard bees can be induced to arrange a safety checkpoint,
(2) That opening positioned in order that the guards can be visually activated by the flight sample of investigating potential thieves,
(3) It could be of profit if the doorway opening location minimized the confusion of returning foragers,
(4) Lastly, its display can be positioned above that entrance to permit the enticing exhaust air to rise and exit there, thus diverting investigating thieves away from the guarded entrance beneath.
NEXT MONTH
We’ll assessment the historical past of robbing screens, and try and design an “improved” one which meets the above {qualifications}, after which check it within the discipline for efficiency.
ACKNOWLEDGEMENTS
I thank my helpers Rose Pasetes, Corrine Jones, and Jacob McBride for his or her many hours of diligent and sometimes tedious discipline and lab work. And to all you donors who assist pay for the price of our analysis!
CITATIONS AND NOTES
