Spring is here and this period is a perfect time to visit our countryside for leisure walks as a way of getting outdoors. Those of us with a keen eye in nature will observe much buzzing activity surrounding flowers and their nectar.

The University of Malta is participating in a COST Action called ConservePlants. Part of the research within this action, led by Marta Galloni and Marta Barberis, is looking at whether and how nectar quality and composition (in particular, specific amino acid content) affects pollinator preferences and behaviours. Another question being posed is whether pollinators themselves in turn affect nectar composition, and if so, how? Therefore, one of the topics Galloni and her team are currently working on concerns the role floral nectar quality plays in influencing pollinator behaviour, and as a result, its effect on plant reproductive success.

Nectar’s role is not simply a ‘reward’ or ‘incentive’ for insect visitors to pollinate plants they happen upon. It is in fact a far more complex affair, as researchers in recent decades have discovered. The concept that plants are somehow able to manipulate visitors in such a way as to enable the optimisation of pollen transfer to pollinators has been strengthened by such research.

Galloni’s lab first addressed such a topic after having stumbled upon bumblebees exhibiting sluggish behaviour after having visited Gentiana lutea flowers. (It is important to note that G. lutea is a species that is protected locally and by regional regulations in the habitats directive). Following such an observation, nectar composition was subsequently investigated. It was found that the nectar of G. lutea was particularly rich in a non-protein amino acid (b-alanine).

As a result, it was hypothesised that b-alanine could play a role in determining nectar attractiveness, enhancing floral fidelity and/or influencing survival and muscular efforts. Results from another paper in fact suggest that the high consumption of non-protein amino-acids (NPAA) from nectar affects insect survival and locomotion. This is due to the transfer of such NPAAs to insect haemolymph.

Despite many studies investigating the topic with particular regard to secondary metabolites (i.e. alkaloids), the concept of partner manipulation may actually also concern the occurrence and/or concentration of primary metabolites in gender-biased nectar. This means that it is not only the nectar quality itself that matters, but also its distribution among the plant population and its sexually different floral stages. Several other questions have been further conceived as a result of such discoveries and are currently being addressed.

Andrea Francesca Bellia is currently reading for a masters in Biology and is a research support officer for SEA-EU at the University of Malta.

Did you know?

• The word cactus originates from the Greek ‘kaktos’, meaning ‘prickly plant of Sicily’. It later emerged that the plant they referred to as kaktos was actually an artichoke.

• Cacti store a lot of water in a short amount of time to make up for the lack of rain in their natural habitat.

• Cacti have a shallow root system that allows them to absorb as much rainwater as possible.

• There are more than 1,500 species of cacti.

• The average lifespan of a cactus plant varies between 10 and 200 years.

For more trivia see: www.um.edu.mt/think

Sound bites

• Every year, our planet encounters dust from comets and asteroids. These interplanetary dust particles pass through our atmosphere and give rise to shooting stars. Some of them reach the ground in the form of micrometeorites. An international program conducted for nearly 20 years has determined that 5,200 tons per year of these micrometeorites reach the ground. That’s more than 4.7 million kilograms!


• Could cactus pear become a major crop like soybeans and corn in the near future, and help provide a biofuel source, as well as a sustainable food and forage crop? Researchers believe the plant, with its high heat tolerance and low water use, may be able to provide fuel and food in places that previously haven’t been able to grow sustainable crops.


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