Plant-Provided Food for Carnivorous Insects: Nectar as fuel for plant protectors

  title={Plant-Provided Food for Carnivorous Insects: Nectar as fuel for plant protectors},
  author={Suzanne Koptur},
Nectar is a sweet liquid produced by plants on various parts of the plant body. Most people are familiar with nectar in flowers, collected by bees to make honey, and utilized by a variety of floral visitors, some of whom serve as pollinators for the plant. Less familiar is extrafloral nectar, produced outside the flowers in extrafloral nectaries and usually not associated with pollination. Plants produce nectar in various ways (Elias 1983; Koptur 1992a), and whether they do it purposefully… 

FLORAL SCENT IN A WHOLE-PLANT CONTEXT Floral volatiles controlling ant behaviour

Across a wide range of plants there is an apparent trade-off in ant-controlling filter strategies between the use of defensive floral volatiles and the alternatives of decoying EFNs or physical barriers.

Loss and gains in ant–plant interactions mediated by extrafloral nectar: fidelity, cheats, and lies

It is proposed that ant–EFN bearing plant interactions serve an excellent and unique model to test the “Geographic Mosaic Theory” of coevolution providing a more clear view of how evolution has structured these plant–animal ecological networks.

Floral volatiles controlling ant behaviour

There is an apparent trade-off in ant-controlling filter strategies between the use of defensive floral volatiles and the alternatives of decoying EFNs or physical barriers, and new evidence of ant repellence by VOCs in temperate flowers is presented.

Extranuptial nectaries in Carapa Aubl. (Meliaceae-Cedreloideae)

The presence of extranuptial nectaries in all 27 species of Carapa Aubl.

Nectar secretion on fern fronds associated with lower levels of herbivore damage: field experiments with a widespread epiphyte of Mexican cloud forest remnants.

The results suggest that ants protect Pl. crassinervata fronds against herbivory, a widespread Central American epiphyte growing on a variety of trees in cloud forest areas of Veracruz, Mexico, which is a new record for this genus and species.

Is extrafloral nectar production induced by herbivores or ants in a tropical facultative ant–plant mutualism?

Contrary to most induction experiments with temperate ecosystem plants, these results demonstrate that tropical plants do not induce one type of defense, and they suggest that the most adaptive defense strategies are different for the two ecosystems.

Extrafloral nectar fuels ant life in deserts

In a seasonal desert of northwestern Argentina, it is shown that biotic interactions between EFN-bearing plants and ants are ecologically relevant components of deserts, and thatEFN- bearing plants are crucial for the survival of desert ant communities.

Mutualism exploitation: predatory drosophilid larvae sugar-trap ants and jeopardize facultative ant-plant mutualism.

This study documents a rather unusual case of predation of adult ants by a dipteran species and demonstrates a top-down trophic cascade within a generalized ant-plant mutualism.



Flower Defenses Against Nectar-Pilferage by Ants

It is surprising that observations in the tropics reveal ants foraging for nectar in flowers only occasionally, and floral nectars are palatable to ants, whereas floral tissues showed highly variable palatability.


Nectars are richer in amino acids if the flowers that produce them are pollinated by settling moths, butterflies and many wasps which, as adults, do not have alternative sources of protein-building materials.


Characteristics of the flowering trees of Acacia terminalis may be interpreted as adaptations for bird pollination, and analyses of foraging dynamics and pollen loads from feathers of passerine birds further support this interpretation.

Facultative mutualism between weedy vetches bearing extrafloral nectaries and weedy ants in California

Vetches (Vicia spp.) were studied in the San Francisco Bay Area of California in the spring of 1978 to determine if these ants protect the vetches from herbivores or seed predators, and analysis of sugar and amino acid composition of extrafloral nectar served as a basis for feeding tests with Argentine ants.


Extra-nuptial nectar glands, by their secretion, attracts to the plants which bear them, hordes of ants which constitute a temporary and changing bodyguard, disputing the presence of all other insects with the exception of their proteges the sugar-secreting aphids, coccids, etc, and resisting often furiously and effectively, the onslaught of ruminants and other large animals.

Ants Like Flower Nectar

Information is presented on flowers visited by ants for nectar; acceptability of various floral nectars to ants; and, responses of ants to potentially toxic compounds in nectar.

Effect of herbivore deterrence by ants on the fruit set of an extrafloral nectary plant, Qualea multiflora (Vochysiaceae)

The role of EFNs acting against herbivores is still under discussion, and plants bearing EFNs may account for up to 31% of the woody individuals and 25% in the cerrado community of Brazil (Oliveira & Oliveira-Filho 1991).

Mutualism in which ants must be present before plants produce food bodies

In the mutualistic relationship between the plant Piper cenocladum and the ant Pheidole bicornis, the production of food bodies is closely tied to the presence of the ants, so that when they are removed, production ofFood bodies nearly ceases and when ants reinvade the plant, production begins again.

Floral and Extrafloral Nectars of Costa Rican Inga trees: A Comparison of their Constituents and Composition1

Differences in composition of the two types of nectar produced by a given Inga species may result from natural selection by mutualists utilizing the nectar as well as non-evolutionary influences of the abiotic and biotic environment.

Use of plant-derived food resources by ants in the dry tropical lowlands of coastal Veracruz, Mexico

There is a significant negative ant-floral nectar and ant-homopteran relationship at any given season; this may reflect the use of alternative resources (floralnectar/ honeydew) with similar nutritional value.