The evolutionary marriage of bees and flowers

​The evolution of bees and flowers is one of the most remarkable examples of co-evolution in nature—where two groups of organisms evolve in order to attract each other in a mutually beneficial relationship.

​140 million years ago there were no bees or flowers but at this time, in the Early Cretaceous, flowering plants (angiosperms) began to appear. Early flowers were likely small, dull, and wind-pollinated, but some began developing features to attract animals like beetles and flies for more efficient pollination.

About 120 million years ago bees began to evolve from wasp-like ancestors that were carnivorous. . Fossil evidence shows early bees trapped in amber had both wasp and bee features. These wasps began to shift to a vegetarian diet, collecting pollen and nectar instead of hunting insects. Through this process bees emerged as a distinct species and they have been evolving ever since to the point where there are now over 20,000 species.

---

Image credit   https://www.museumoftheearth.org/bees/evolution-fossil-record

The driving force of pollen
Pollen is essential for the reproduction of both bees and flowers this drove co-evolution for mutual success. Adult bees evolved behavioural and physiological adaptations to gather and transport pollen more efficiently. As bees adapted to collect nectar and pollen, flowers adapted to make their nectar and pollen resources more accessible and rewarding. In particular, they developed:

• Bright colours - especially blue and violet, which bees see very well
• Nectar guides—patterns that guide bees to nectar
• UV markings that only bees can see
• Unique shapes that favour certain bee species​

Bees, in turn, developed:

• Fuzzy bodies to trap and carry more pollen
• Branched hairs and pollen baskets (corbiculae)
• Complex tongues in some groups to reach deep nectar​

Over time some flowers  formed specific relationships with certain bee species (e.g., buzz pollination in tomatoes, requiring bumblebees). Some flowers, like bee orchids, even mimic female bees, tricking male bees into "pseudocopulation" for pollination (image right)

---

A mutually beneficial relationship
Flowers need bees to distribute their pollen to other flowers of ther own species in order to complete the fertilisation process. Bees visit flowers to harvest their resources which include pollen, nectar, oils, and/or resins, depending on the plant species.

Pollen, the most protein-rich of these rewards, is essential to bee reproduction. Once gathered, adult bees typically mix pollen with nectar and glandular secretions to form a nutritious “bee bread,” which forms the diet of larval bees.

Nectar is composed chiefly of carbohydrates and water, with low levels of amino acids, lipids, proteins, and various vitamins and minerals. It is this sugar-rich food source that fuels adult bees, butterflies, and a myriad of other flower visitors, such as bats and hummingbirds.

Oils and resins are secreted by some flowers to attract bees. Specialized floral glands produce calorie-rich, medicinal oils that are regularly collected by a few bees and mixed with pollen and nectar for feeding and medicating larvae. Most likely, such flower resins first evolved to protect the plants from herbivores or disease. Eventually bees came to use them as a food source, and as a resin for constructing antimicrobial and waterproof nests.

Co-evolution of lavender and bees
Lavender and bees have co-evolved through a long and mutually beneficial relationship shaped by natural selection over millions of years . This co-evolution has influenced the plant’s traits and the behaviour and sensory adaptations of bees. Here's how that relationship has unfolded: Here are some of the ways in which lavender has adapted to attract bees in order to help it pollinate and thrive.

1. Colouration Lavender flowers are blue to violet, which bees see very well (they perceive UV, blue, and green best). The petal patterns often have UV nectar guides — invisible to us, but like landing lights to bees.
 
2. Scent Lavender produces strong aromatic oils (linalool, camphor, etc.), which help attract bees from a distance. The fragrance acts as a signal of nectar availability, reinforced through learning.
 
3. Nectar and Pollen Production Lavender produces copious nectar with a high sugar content, ideal for honey production. It also offers pollen, a key protein source for bee larvae. Its long flowering season (summer to early autumn) provides sustained forage.
 
4. Floral Structure Lavender has tubular flowers that exclude many non-pollinators but match the tongue length of bees (especially long-tongued bumblebees and honeybees). The structure rewards the right pollinators, encouraging flower constancy.
 
Some of the ways that bees have adapted to lavender
1. Colour Vision Bees have evolved to see UV and blue, perfectly matching lavender's flower colour range. Their vision helps them detect lavender from afar and locate nectar guides.
 
2. Learning and Memory Bees learn and remember lavender’s scent, shape, and location — increasing efficiency. This leads to flower constancy — bees repeatedly visit lavender, aiding effective pollination.
 
3. Tongue Length Species like bumblebees (Bombus spp.) have long tongues suited to lavender’s flower tubes. Over generations, tongue length and flower depth have co-adjusted for efficiency.
 
To summarise, lavender and bees exemplify co-evolution, where plants evolve traits that attract and reward bees and bees evolve traits to detect, access, and remember those plants. This leads to strong ecological interdependence, promoting both biodiversity and resilience in pollination networks. These evolutionary adaptations benefit lavender through more efficient pollination → higher seed set → greater reproductive success. They benefit bees through more reliable nectar and pollen supply sustained over a long flowering season.

NJ & chatgpt

Evolution of Bees https://www.museumoftheearth.org/bees/evolution-fossil-record


This video, made with the help of AI, explains why bees find lavender so attractive but the features that attract bees are the result of adaptations brought about through natural selection as bees interacted with the plant over millions of years

---