Although exotic species typically pose a serious threat
to lizard-plant mutualisms, a gecko endemic to
Reunion Island, Phelsuma inexpectata, has been
consistently observed to rob pollen pellets from
introduced European Honeybees as they foraged on
flowers. Over a period of 140 minutes, a total of 78
attempts at pollen theft were recorded, of which 40%
were successful.
However, 79 seeds from this plant species were
discovered in the gut of a single Green Iguana (Iguana
iguana). The Green Iguana has been implicated in the
dispersal of seed from over 35 different plants, and
ingestion of seed by the lizards has also been shown to
significantly increase both the success and rate of
germination for some species. Higher germination
rates (and thus enhanced chances of survival) have
been reported for other frugivo-
rous lizards: in one trial, 90.7%
‘
of Ziziphyus rignoni seeds
ingested by Rhinoceros Iguanas
(Cyclura cornutua) and Ricord’s
Rock Iguanas (C. ricordii) germi-
nated after 8 days, compared
with just 3.7% for controls.
Another study found that
’
Pithecellobium juliflora seeds that
had passed through the gut of the
Some plant species are obligatorily dependent on
Mexican Spiny-tailed Iguana (Ctenosaura pectinata)
saurochory. For example, seeds of Melocactus violaceus had significantly lower bruchid infestations (32.7% for
will only break dormancy if they pass through the
ingested vs 94.6% for controls).
digestive tract of a lizard, making their seed dispersal
agent, the Amazon Lava Lizard (Tropidurus torquatus) Even when successful germination is unaffected or
indispensable. The seeds of Spondias mombin are
negatively impacted by the passage of seed through a
unusually large, measuring 20mm across, and hence
lizard’s digestive tract, it cannot be concluded that the
are unlikely to be dispersed by small animals or wind. reptile does not contribute to seed dispersal. Seeds are
The G REEN I GUANA has been
implicated in SEED DISPERSAL of over 35
PLANTS , and ingestion of seed by the lizards
ENHANCES GERMINATION .
Green Iguana (Iguana iguana). Image by
Andrey Shcherbukhin .