Nest Biology of the Stingless Bee Scaptotrigona postica
This is a modal window.
The media could not be loaded, either because the server or network failed or because the format is not supported.
Formal Metadata
| Title |
| |
| Alternative Title |
| |
| Author | ||
| Contributors | ||
| License | No Open Access License: German copyright law applies. This film may be used for your own use but it may not be distributed via the internet or passed on to external parties. | |
| Identifiers | 10.3203/IWF/C-1351eng (DOI) | |
| IWF Signature | C 1351 | |
| Publisher | ||
| Release Date | ||
| Language | ||
| Other Version | ||
| Producer |
Technical Metadata
| IWF Technical Data | Film, 16 mm, LT, 194 m ; F, 18 min |
Content Metadata
| Subject Area | ||
| Genre | ||
| Abstract |
| |
| Keywords | ||
| IWF Classification |
Transcript: English(auto-generated)
00:04
Nest biology of the stingless bee, Scaptotrigona postica. Stingless bees are the closest relatives of the honey bees. They are highly eusocially organized. They build permanent nests generally in cavities and lay up stores of food.
00:22
They occur in tropical and subtropical regions. Of the 300 or so known species, 200 live in South America. Scaptotrigona postica is common in Brazil. Large colonies number more than 100,000 individuals.
00:41
The worker is about the size of a housefly. Foragers are easy to observe while visiting flowers. Like the honey bees and the bumble bees, they collect pollen in their baskets. All that can normally be seen of a colony is the nest entrance,
01:00
which the bees have constructed themselves. Guards keep watch at the entrance funnel. An observation box provided with glass walls allows one to follow the activities inside the nest. The building material, known as cerumen, is a mixture of wax and collected plant resins. The nest is divided into a brood cell and a storage pot area.
01:25
The brood chamber is enveloped in several layers of a thin, irregularly shaped covering called the involucrum. This insulating and protective sheath has many perforations. To the right, part of the brood nest has been exposed. It consists of several layers of horizontally arranged combs,
01:44
one cell in thickness each. New cells are always added at the edges of the combs. The bees build several layers of combs simultaneously. The brood cells are used only once, but the cerumen is recycled. In this way, the brood nest is continually being renewed,
02:03
growing from the bottom upwards in the process. Supporting pillars are scattered between the combs. The storage area is outside the involucrum. For storing pollen or honey, hazelnut to walnut sized pots are built. They are constructed in irregular clusters
02:21
beside or on top of one another. In contrast to the brood cells, they are reused time and again. Stingless bees are important pollinators in tropical countries. They are flower constant, like the honey bees, and can collect both nectar and pollen at the same time. Scapto trigona workers start foraging at the age of 25 to 30 days.
02:46
Not until then are they fully pigmented black. Their life span is 50 to 80 days. Returning pollen foragers with laden corbiculi first briefly test an open pot
03:02
to ascertain whether it is a pollen container. Then they alight on the edge and rake off the pollen load with their hind legs. Finally, they clean their legs. Young house bees take over the further processing of the pollen. It's firmly pressed down into the pot
03:22
and moistened with saliva. This affects fermentation and preservation of the pollen supply. Nectar foragers crawl into a honey pot and disgorge the contents of their crop into it.
03:43
The honey thus stored remains thin. Full food pots are sealed. Pollen pots are provided with a small cap-like air chamber. Fermented pollen is the food of the house bees. A whole group of young, still brown-pigmented nurse bees
04:02
are feeding at a pollen pot which has just been uncovered. They are recognisable on account of their light-coloured scutella. Later, the bees enter the pots to continue feeding. The pollen pots are only opened singly and then emptied completely. Liquid nutriment is exchanged tropholactically among nestmaids.
04:33
Stingless bees defecate inside the nest. At the bottom of the nest, waste dumps are set up containing, besides faeces, larval cocoons, exuvee, dead bees,
04:43
as well as other refuse. Nurse bees produce yellowish, sausage-shaped dung full of pollen residues. The heaps of excrement formed overnight are disposed of during the daytime. Older, black-pigmented flight bees make pellets out of the refuse.
05:04
Bees are then carried outside the nest in their mandibles. Dead bees are also removed in this way. There are no free structures inside the nest. Each area is connected to the others by pillars or cross struts,
05:23
which also serve as gangways. Many of the galleries are paper-thin. Work is continually in progress on this system of supports. Building material is brought along by the workers in their jaws and pre-masticated.
05:45
Towards the edges of the nest, the pillars are splayed out. The corners of the outermost nest covering are thickly encrusted with propolis. While still under construction, the storage pots are already given a shiny, waterproof inside coating of wax.
06:03
As yet unused pots are light brown and translucent. Each layer of combs begins with a single stalked cell. Further cells are added, giving rise to a regular pattern. The brood cells are also lined with wax.
06:22
New cells are never placed next to one another at the edge of the comb, so that neighbouring cells are always in different stages of completion. The construction of a cell takes several hours. The 8 to 25 days old bees, recognisable by their light scutella, are also functioning as building bees.
06:42
Their dorsally situated wax glands are secreting actively, the whitish scales protruding far out of their tergite pockets. While shaping the walls of the cell, the bee curls up inside and uses her abdomen to gain purchase.
07:00
With her mandibles, she masticates the collected cerumen. One never sees several bees working together on one cell at the same time. The upper margin of a newly built cell
07:21
is shaped to protrude above the level of the comb surface. It is tapered slightly and then smoothed off. Not until several new cells have been completed does the queen come to oviposit. Stingless bees exhibit strong female cast dimorphism. The egg-laying physiogastric queen
07:41
is about five times as heavy as a worker and unable to fly. Her hind body is distended with the enlarged ovaries. The less strongly pigmented intersegmental membranes are stretched, making the individual brown terga show up distinctly. The queen flutters all the time with her laterally outstretched wings.
08:02
This causes the tips to erode very rapidly. The queen first inspects newly built cells in the brood nest. Whenever she encounters workers, they retreat before her with ritualised wing beating.
08:28
As soon as she stops anywhere, the fixing queen is immediately encircled by a group of nurse bees. Time and again, individual bees antonate with her, then retreat and beat their wings.
08:42
Surrounding the queen in this manner is quite unlike the court of the honeybee. The queen is only encircled for a short while before egg-laying and is never licked and fed. The workers meeting her exhibit aggressive rearing and mandible threatening. An egg-laying phase is accompanied by hectic activity.
09:06
The queen approaches the completed cells and ascertains whether they are already filled with larval food. In stingless bees, the brood cells are mass provisioned before oviposition with a food supply which lasts throughout the larval period.
09:21
The provisions consist of glandular secretions together with regurgitated honey and pollen. As the queen approaches a cell, the workers drop back to the edge of the comb.
09:48
The queen usually eats some of the larval food herself before depositing an egg. While laying, she engages in intensive antenna contact with that worker which immediately afterwards seals the cell.
10:09
Several nurse bees are filling the brood cell three-quarters full of larval food. The queen only takes a very small amount.
10:26
During laying, two contractions of the hind body are to be seen. In the middle of the cell, the egg floats vertically in the food solution.
10:42
In the course of one series of egg-laying, at least 20 cells are oviposited within only a few minutes. Apart from larval food, the queen eats trophic eggs produced by workers of the nursing age.
11:05
These eggs are laid on the rim of a provisioned cell. They are rounder and thicker than normal eggs. If the queen does not discover a trophic egg in time, it is eaten by a worker. The worker in the centre is about to lay a trophic egg.
11:49
Immediately following the queen's oviposition, a worker starts to seal up the cell. The raised collar is bent inwards. From outside, the bee kneads the rim of the cell with her mandibles,
12:01
stemming the tip of her sharply curled abdomen against it from within. She controls the progress of the work all the time with her antennae.
12:21
Finally, the cell cap is carefully smoothed. Closing a cell may take from two to three minutes. As with all Hymenoptera, the males of the stingless bees are produced from unfertilised eggs. The drones of Scapto trigona cannot be distinguished from workers with the naked eye.
12:41
They develop in the same type of brood cell scattered all over the combs. Development takes five to six weeks in the case of both workers and drones. Queen cells are about four times as large as normal brood cells. The smooth wax coating of the inner wall is particularly recognisable here.
13:05
The queen cells are situated only at the margins of completed combs and are connected to the involucrum by pillars. Several bees cooperate simultaneously to build a queen cell. It is tapered towards the top
13:20
so that the collar is finally no larger than that of an ordinary brood cell. The queen cell is filled with normal larval food. It is only the larger quantity which determines a queen. Her development takes several days more than that of the workers and drones.
13:45
If no more completed cells are available, the queen leaves the brood nest. The hectic activity subsides. The finished comb clearly demonstrates how the bumpy surface between the cell caps is smoothed over with an application of cerumen.
14:04
Stingless bees regulate the brood nest temperature just as honey bees do. If there is a sharp drop, building activity ceases. All the bees, both old and young, cluster together to warm the combs. In cool weather, the entrance is also sealed.
14:26
Cold areas of the nest, such as the cover glass here, are coated with cerumen. If the brood nest heats up too strongly, a cool draft of air is created by the bees fanning their wings.
14:43
Part of the involucrum has been removed to observe the brood emerging. Older combs appear light brown because the surface coating has already worn off again. Young bees, ready to emerge, cannot free themselves from the cells on their own.
15:03
Nurses gnaw away the caps of the cells so that the young, soft and pale bees can crawl out. Immediately afterwards, house bees begin to dismantle the empty cells.
15:27
The freshly emerged young groom their bodies and smooth their wings. The young bees spend the first few days of their imaginal life
15:44
in spaces above the brood nest in so-called nurseries. During this period, the cuticle hardens. When they are about eight days old, the medium brown coloured workers begin to participate in household activities.
16:00
Stingless bees are by no means defenceless. They defend the nest entrance successfully against much larger predatory insects. Wasps and alien bees are attacked, bitten and mauled.
16:25
If larger enemies approach the entrance hole, the bees release alarm substances. These pheromones cause hundreds of bees to pounce on the intruder. They bite into the hair and external orifices. This also constitutes highly effective defensive behaviour.