“….and today we’re talking about a tiny, little farmer. But more on that later.”
(Messor Ibericus)
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com.
Queen Length of the Iberian Harvester Ant
The queen of Messor barbarus (Iberian Harvester Ant) measures 16 mm (0.63 in). How many objects fit into the queen’s length (if the object is shorter) or how many queens fit into the object’s length (if the object is longer)?
a) The length of a Spanish saffron crocus stigma
A single red stigma (the part that becomes saffron) from Crocus sativus, harvested across Spain, measures about 30 mm long before drying.
b) The width of a traditional Andalusian olive
A large Manzanilla or Gordal olive from Andalusia measures about 20 mm across at its widest point.
c) The length of a grain of Spanish Calasparra rice
A single uncooked grain of Calasparra or Bomba rice measures about 7 mm.
Question: How many fit into each queen length comparison?
A) 2.9 Iberian Harvester Ant queens go into the length of a Spanish saffron stigma
B) 2.3 Iberian Harvester Ant queens go into the width of an Andalusian olive
C) 2.3 grains of Calasparra rice go into the length of an Iberian Harvester Ant queen
Worker Length of the Iberian Harvester Ant
The worker measures 14 mm (0.55 in). How many objects fit into the worker’s length (if the object is shorter) or how many workers fit into the object’s length (if the object is longer)? Major workers (soldiers) 9–14 mm, minor workers 4–9 mm.
a) The length of a Portuguese cork oak acorn
A mature acorn from the cork oak forests of the Alentejo region measures about 35 mm long.
b) The diameter of a Spanish jamón ibérico slice
A properly cut slice of jamón ibérico de bellota is about 6–7 cm across; we’ll use 65 mm for a large round slice.
c) The length of a single seed of Spanish harvester ant forage (Messina)
Harvester ants of this species commonly collect seeds of Messina (Melilotus spp.); one seed is about 2.5 mm long.
Question: How many fit into each worker length comparison?
A) 2.5 Iberian Harvester Ant workers go into the length of a Portuguese cork oak acorn
B) 5.6 Iberian Harvester Ant workers go into the diameter of a Spanish jamón ibérico slice
C) 4.6 Messina seeds go into the length of an Iberian Harvester Ant worker
Fast Facts
Very common throughout most of Spain and Portugal except the wettest northern Atlantic areas (Galicia, Asturias, Basque Country). Abundant in:
• Andalusia
• Extremadura
• Castilla-La Mancha
• Madrid region
• Catalonia
• Valencian Community
• Aragon
Prefers open, sunny habitats: dry grasslands, olive groves, abandoned fields, roadsides, Mediterranean scrubland.
Workers will “rescue” seeds that have germinated in the granaries by biting off the radicle (root) to prevent them from sprouting inside the nest.
They are very heat-tolerant and forage at surface temperatures above 50 °C (122 °F) when most other ants stay underground.
Nuptial flight: Usually March–May (sometimes autumn in southern areas) after the first heavy spring rains.
Colony founding: Claustral (queen seals herself in and raises the first nanitic workers without foraging).
Mature colonies: Can reach 10,000–50,000+ workers in old nests (10–20 years old). Very long-lived queens (15–20+ years documented).
Trails and trunks: They create cleared, permanent trunk roads radiating from the nest entrance, sometimes tens of meters long, completely free of vegetation.
Nest structure: Deep nests (often 2–4 m deep, sometimes up to 8 m) with dozens or hundreds of chambers for seed storage, brood, and the queen. Entrance is usually a single large hole surrounded by a crater of excavated soil and seed husks.