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Relative compound eye size differences in Bombus species – investigating the influence of habitat, sex and caste

Karlsson, Emelie (2018) BIOK01 20172
Degree Projects in Biology
Popular Abstract
Bumble bee compound eye sizes in different climates

Bumble bees are important pollinators with over 250 species spread over the world. One could even argue that they are the cornerstones of life as we know it, considering their immense task of pollinating almost everything we eat, as well as everything that what we eat eats. But how does the bumblebee do all this, in all these vastly different places of the earth with such contrasting environments?

Bumblebees are performing their ecosystem service whether they are found in environments like the tropical Brazil or the tundra in northern Sweden. But the tundra and the tropical climate are very different from each other, both in terms of lighting conditions as well as structural... (More)
Bumble bee compound eye sizes in different climates

Bumble bees are important pollinators with over 250 species spread over the world. One could even argue that they are the cornerstones of life as we know it, considering their immense task of pollinating almost everything we eat, as well as everything that what we eat eats. But how does the bumblebee do all this, in all these vastly different places of the earth with such contrasting environments?

Bumblebees are performing their ecosystem service whether they are found in environments like the tropical Brazil or the tundra in northern Sweden. But the tundra and the tropical climate are very different from each other, both in terms of lighting conditions as well as structural complexity. The tropical climate offers a very complex environment, as the illumination varies dramatically depending on location and time during the day, with thick canopy blocking out most of the sky and predators luring behind every other flower you set out to pollinate. How are the bumblebees adapted to this?

The secret lies (partially) in their eyes. Little is known as to how their visual organs are adapted to the different environments and the differences in abundance of light, however, external observations of bees indicate there is great diversity in the shape and placement of their eyes. By comparing the areas of the eyes using 3D-modelling on 17 bumblebee species from arctic, temperate and tropical environments, we have investigated whether the size of the eyes is indeed related to the climate they live in.

The fact that some environments are more challenging to navigate within, will promote development of better vision in order for the bumblebee to find its way to the right flower – and avoid finding its way into someone else’s stomach. In the case of the compound eye, bigger actually does mean better. Therefore, the tropical bumblebee species seem to try and maximize the eye area to body size ratio – e.g. to develop the biggest eyes they could possibly carry (being not so big themselves).

On the other side of the globe, we have the tundra. Situated above the treeline, these areas do not get the same shade as the tropics. The days are extremely long during summertime, which of course gives the bumblebees that live there a somewhat different outset than their tropical relatives. As a result, our study shows that the bumblebees in this climate have smaller eyes than their tropical counterparts.

The size of the bumblebees’ compound eyes is therefore very much related to the climate they live in. The differences can be explained by the differences in light, complexity of the environment and is possibly also related to the differences in predation pressure. This has led to bigger eyes in the tropical bumblebees, to make sure they can keep on doing what they do best – no matter the circumstances.

Emelie Karlsson
Examensarbete för kandidatexamen i Biologi 15 hp 2017
Biologiska institutionen, Lunds Universitet
Handledare: Emily Baird och Pierre Tichit
The Vision Group, Lunds universitet (Less)
Please use this url to cite or link to this publication:
author
Karlsson, Emelie
supervisor
organization
course
BIOK01 20172
year
type
M2 - Bachelor Degree
subject
language
English
id
8963803
date added to LUP
2018-12-04 11:50:58
date last changed
2018-12-04 11:50:58
@misc{8963803,
  author       = {Karlsson, Emelie},
  language     = {eng},
  note         = {Student Paper},
  title        = {Relative compound eye size differences in Bombus species – investigating the influence of habitat, sex and caste},
  year         = {2018},
}