January 31, 2022

Pinning Insects for the Museum’s Collections:

Where skill meets art, and sometimes a little luck!

Pinning Insects for the Museum’s Collections

As part of the Manitoba Museum’s entomology collection, we house over 60,000 pinned insects, true bugs, and arachnids. In addition, there are a further ~3000 invertebrates preserved in alcohol, also referred to as “wet” specimens. While the majority of the collection are pinned insects in their adult form, there are also examples of the many and varied life stages that occur prior to the adult form, including egg, larval, nymph, and pupal forms. It is important that a scientific collection contain representatives of these life stages (including males and females of each), as they can and do look very different within any given species.

The Manitoba Museum is a research and collections-based museum whose mandate is to collect and preserve both the natural and human histories of the province for present and future generations. Curators conduct research throughout the province in their respective fields of expertise. Specimens are collected during field seasons and are brought to the museum for preparation and subsequent study. Before specimens can be handled and made accessible for study, they must be prepared to maintain their long-term preservation. Fossils need to be exposed from their matrix, plants need to be dried and mounted, and birds and mammals transformed into skins and skeletons. Insects too, must undergo a preparation process in order to stabilize them for storage, and to make them safer to handle. This is where skill meets a bit of art, and sometimes a little luck!

Open storage drawers  containing many neatly organized pinned butterflies.

The Manitoba Museum’s entomology collection represents most of all the very diverse groups and species that occur in Manitoba. Image: © Manitoba Museum

A small pile of winged ants on a white surface next to a hand-written note reading, "Collected by R. Mooi / Sept 10/2020 / Winnipeg - on wall".

It all starts here – Dr. Randy Mooi, Curator of Zoology, has brought in some dead carpenter ants with collection information. Image: © Manitoba Museum

A Confusing Bumblebee specimen hanging upside-down from a the pink and yellow flower of a Darkthroat Shootingstar plant model.

Once specimens are carefully collected and brought to the museum, a decision must be made on how a particular insect will be preserved. Part of this decision is based on what type of insect (invertebrate) it is, but also how we may want use the specimen afterward. Typically, insect specimens for scientific use are pinned in a traditional manner according to international museum standards where all parts are positioned symmetrically, and anatomy used for identifying characteristics are not obscured. If a specimen will be used for educational purposes, or included in an exhibition in one of our galleries, the pinning is slightly different so that a more life-like pose is achieved. Certain groups or forms, such as a caterpillar (larva), or other worm-like animals, would simply shrivel up if it was pinned, and would not be very recognizable. These types preserve better as a whole body stored in a vial with alcohol as a wet specimen.

 

I pinned this Confusing Bumblebee (Bombus perplexus) in a life-like pose, as it would naturally be, collecting nectar. Our Diorama Specialist, Deborah Thompson then attached it to a Darkthroat Shootingstar plant model she expertly made. This pair is now installed in the new Prairies Gallery. Image: © Manitoba Museum

Three plastic cups placed inside a larger plastic container with a snap-lid. In each of the plastic cups are a few insect specimens.

When adult insects are collected, they typically become very dry and brittle by the time they are brought into the museum. Handling them is difficult without causing damage, as tiny legs and antennae can easily break off. In order to manipulate and pin them in the correct position, they must first be re-hydrated into a softened state. Plastic containers with good sealing lids are used as a re-hydrating environment. The container is filled with a couple of centimetres of distilled water with some alcohol added to guard against any mould growth. Insect specimens are then placed on top of a piece of rigid foam which is floated within the container.  After a few days, the specimens are checked to see if they are pliable enough for the wings and legs to easily be moved. Small flies could be ready in a few days, large beetles with thick exoskeletons and strong ligaments, could take several days.

 

Insects are placed in a re-hydrating container to soften, and make them pliable for the pinning process. Image: © Manitoba Museum

Once in a softened state, the insect is ready for the pinning process. The insect is gently held while a main pin is inserted through the thorax, just below the base of the forewings, and placed perpendicular to the plane of the body. Special entomology pins are used as they are made of metals that will not corrode when in contact with the insect. They come in different gauges to be used with the varying sizes of insects. A large insect, such as a butterfly, will require a thicker pin for sturdiness, and a very thin gauge pin would be used for smaller insects. Anything even smaller, or extremely fragile is “pointed”. That is, where an insect is too small to have a pin inserted, it is instead carefully glued to the ‘point’ of a small triangle of archival card stock and the main pin is then inserted through the point. This main pin is now the only way the specimen can safely be handled.

A monarch butterfly specimen positioned on a pinning board with strips of glassine and straight pins. In the background are a magnifying glass and various pinned insects in storage containers.

A pinning board is used to properly position a large butterfly specimen. Image: © Manitoba Museum

A close up on a fly specimen held in place with several straight pins.

Numerous support pins are used to position the legs and wings of this fly specimen. Image: © Manitoba Museum

When the main pin has been properly placed, the legs, wings, and antennae must then be positioned. A pinning board made of soft balsa wood or dense foam is used for specimens with large wings such as butterflies, moths, dragonflies, or grasshoppers. It has a trough where the body can be lowered, and the wings can then be spread over the flat surfaces of the boards on either side and supported. Spreading the wings properly is a bit like the game “Twister” for the fingers. Insect wings are incredibly fragile, so carefully coaxing them away from the insect’s body without damaging them takes some practice. Add to that, the wings of Lepidopterans (butterflies and moths) are covered in fine, microscopic scales that aid in flight, waterproofing, and coloration that will break off, like dust, if touched. Forceps are gently used to spread the forewing out from the body on one side, and while holding that in place, the hind wing on the same side, is brought out and positioned. Once both wings on one side are in the proper position, a strip of glassine is placed gently over them. Glassine is a smooth translucent paper that will not abrade the scales of the wings. Pins are then inserted just through the paper and into the underlying pinning board to hold everything in place. This process is then repeated with the wings on the other side. The antennae and legs are then moved into place, slightly away from the body, and support pins are inserted into the board to hold them there. This is done so that the legs do not obscure any important identifying characteristics.

After the insect is pinned into the correct position, it is left to dry. Depending on the size of the insect, it may dry in a few days, larger beetles and dragonflies could take over a week. When it is dried, the positioning pins are very carefully removed and it is now ready for data labels to be attached on the main pin below the specimen. Labels are printed on archival paper and contain all the pertinent data about the specimen such as the identification, who collected the specimen, and when and where it was collected. This data is also entered into our collections management database. As with all specimens in our collections, it is extremely important to keep each specimen together with its data. The data proves that this exact species occurred in this time and place – it’s recorded proof of that biodiversity snapshot of that time. If the data labels ever became separated from its specimen, its intrinsic scientific value is greatly diminished, or completely lost.

Looking down a corridor at a glass display wall of pinned insects.

The vast diversity of insects of Manitoba’s Boreal Forest is showcased in the Boreal Gallery and contains over 700 invertebrates. Image: © Manitoba Museum/Ian McCausland

Museum collections all over the world apply these same international techniques and standards when preparing and storing specimens for study. This aids in maintaining consistency between museum collections, and have changed very little over the past several hundred years.

Two images side by side. On the left is a black and white photo of rows of pinned insects. On the is a colour photograph of similar insects pinned in a similar fashion.

Left: Sir Joseph Banks Insect Collection (1743-1820) Image: © The Trustees of the Natural History Museum, London. Licensed under the Open Government Licence

Right: Present-day insect collection at the Manitoba Museum. Image: © Manitoba Museum

Janis Klapecki

Janis Klapecki

Collections Management Specialist – Natural History

Janis Klapecki obtained a B.Sc. from the University of Manitoba, specializing in Zoology and Botany. She also holds a certificate in Managing Natural History Collections from the University of Victoria, BC. Janis has over 20 years experience…
Meet Janis Klapecki

The Weird World of Plant Sex

A small plant growing from a wooded ground. The plant is topped by a flower with large, drooping pink petals. Two large leaves encircle the stem at the base.

On the surface, plant sex seems pretty simple. Birds and bees transfer pollen from one flower to another and voila: seeds are produced. But, like most things in life, plant reproduction is much more complicated than initially meets the eye.

Finding a Mate

For starters, plants are not like mammals when it comes to gender. Only about 5-6% of all flowering plant species are dioecious, that is, having separate “males” (i.e. producing only sperm-containing pollen in stamens) and “females” (i.e. producing only eggs in pistils). The most familiar dioecious plants to most people are Manitoba Maples (Acer negundo; left, below), willows (Salix spp.) and marijuana (Cannabis sativa). However, the vast majority of plant species are monoecious, producing both sperm AND eggs in a single plant. This strategy makes sense for organisms that can’t move around to find a mate. When you make both sperm and eggs, your possible number of romantic encounters doubles. Most of the common garden flowers that we love, such as lilies, roses, tulips and orchids, are monoecious.

A close-up of a tree branch with green leaves and elongated green winged seeds.

Some plant species, like Manitoba Maple (Acer negundo) have separate male and female trees. This tree is female, and has produced winged seeds.
Image: © Manitoba Museum

Photo looking down at a Western Red Lily in the grass. The Orange-red flower has six petals, with a pistil in the centre, surrounded by six small stamens.

The flowers of Western Red Lily (Lilium philadelphicum) have a single pistil in the center, which contains the eggs, and six sperm-producing stamens surrounding it.
Image: © Manitoba Museum

A mid-range photo of a White Spruce tree. The nearest branch has many brown cones on it.

The female cones of White Spruce (Picea glauca) are usually near the top of the tree and the male cones near the bottom, to prevent self-fertilization.
Image: © Manitoba Museum

Some species are cosexual, with both stamens and pistils in the same flower (e.g. the Western Red Lily, Lilium philadelphicum; centre, above). Other species produce separate male and female cones or flowers on different parts of the same plant, or at different times of the year. For example, White Spruce (Picea glauca. Right, above) trees produce male cones at the bottom of the tree and female cones at the top. Alder (Alnus spp.) shrubs typically produce their male flowers first, and then their female flowers afterwards. The separation of pollen- and egg-production in either space or time, helps prevent self-pollination and inbreeding.

Two pressed and preserved branches of Four-wing Saltbush. The two branches are laid falt on a large sheet of white paper, with specimen details typed at the bottom.

However, even plants with separate “males” and “females” may be able to change sex in a pinch. Imagine what would happen if all the plants in a certain area happened to be female. No babies would be made at all! Scientists have described instances of plants switching from making female flowers to male flowers in response to environmental conditions (Freeman et al. 1980). Light levels, soil fertility and temperature are some of the factors known to alter floral sex in certain species (Varga and Kyto viita 2016; Freeman et al. 1980). When resources are scarce or growing conditions poor, making sperm is less energy-intensive than making eggs and seeds. Thus, for example, a dioecious tree may produce male flowers when it is young and short, and female flowers when it is older and taller, as larger trees capture more light.

 

Left: Four-wing Saltbush (Atriplex canescens) plants have been documented as changing gender after particularly stressful weather events, like cold temperatures and drought (Freeman et al. 1984). Image: © Manitoba Museum, 29685

Going Solo

But we have only scratched the surface of plant weirdness. Sometimes, flowers will not receive any pollen.  This means that all the energy invested in egg production will go to waste. In the name of efficiency, some species, like sunflowers (Helianthus spp.), self-pollinate by curling parts of their pistils around their stamens. In other species, a process called agamospermy results in the egg maturing into a seed without being pollinated at all. It’s kind of like a virgin birth, with the offspring being genetically identical to the parent plant.

Other species, often those in cold, alpine or arctic climates, don’t even bother producing seeds; they just make tiny clones of themselves called bulbils. This is a kind of asexual reproduction. Once the bulbil is large enough, it detaches, perhaps when a stiff breeze is blowing, and grows into a new plant. That would be like growing a tiny version of yourself on the outside of your belly (like a giant pimple). Then one day it would just fall off and become a new person that looks exactly like you. Native plants like Bulb-bearing Water-hemlock (Cicuta bulbifera) and Viviparous Sheep’s Fescue (Festuca viviparoidea), and house plants like Kalanchoe (Kalanchoe spp.) use this technique to reproduce.

Plants also engage in vegetative reproduction. This is when plant parts, like leaves or stems, that become detached go on to grow roots and become new plants. Many cacti and other succulents, can do this: cactus “pads” (actually swollen stems) that become detached grow into new plants under the right conditions. For humans, this would be like removing a leg, and then having it grow into a clone of yourself. The “parent” would then grow a new leg to replace what was lost, kind of like what the Marvel Cinematic Universe character Deadpool did in the movie sequel (his whole body regrew from his head!).

A ywllow sunflower in front of a blue sky with faint whisps of white cloud. Near the centre of the sunflower are two small, black and yellow striped pollinator insects.

Sunflowers (Helianthus annuus) can pollinate their own seeds if they have to, but production is lower and the offspring are not as genetically diverse. Image: © Manitoba Museum

Pads of several low-growing Plains Prickly-pear Cactus growing among grass and brush. A yellow flower grows from one of the pads.

Cactus pads of Plains Prickly-pear Cactus (Opuntia polyacantha) that become detached can grow into new plants. Image: © Manitoba Museum

Plants also engage in vegetative reproduction. This is when plant parts, like leaves or stems, that become detached go on to grow roots and become new plants. Many cacti and other succulents, can do this: cactus “pads” (actually swollen stems) that become detached grow into new plants under the right conditions. For humans, this would be like removing a leg, and then having it grow into a clone of yourself. The “parent” would then grow a new leg to replace what was lost, kind of like what the Marvel Cinematic Universe character Deadpool did in the movie sequel (his whole body regrew from his head!).

Plants have had to evolve some ingenious ways to ensure their reproductive success because they are rooted in one spot. Imagine how much stranger our lives would be if humans reproduced like plants.

 

References

Freeman, D.C., K.T. Harper, and El L. Charnov. 1980. Sex change in plants: old and new observations and new hypotheses. Oecologia, 47: 222-232.

Freeman, D.C., McArthur, E.D., and K.T. Harper. 1984. The adaptive significance of sexual lability in plants using Atriplex canescens as a principal example. Annals of the Missouri Botanical Garden, 71: 265-277.

S. Varga, M.-M. Kyto viita. 2016. Light availability affects sex lability in a gynodioecious plant. American Journal of Botany, 103: 1928-1936.

Dr. Diana Bizecki Robson

Dr. Diana Bizecki Robson

Curator of Botany

Dr. Bizecki Robson obtained a Master’s Degree in Plant Ecology at the University of Saskatchewan studying rare plants of the mixed grass prairies. After working as an environmental consultant and sessional lecturer…
Meet Dr. Bizecki Robson