The common name “daddy long legs” frequently sparks curiosity about these creatures, particularly concerning their ability to survive without food. Understanding how long these arthropods can endure periods of scarcity involves examining their diverse forms and the biological strategies they employ.
Defining “Daddy Long Legs”
The term “daddy long legs” can be confusing because it refers to two distinct types of arachnids: Harvestmen (Order Opiliones) and Cellar Spiders (Family Pholcidae). Harvestmen are not true spiders; they possess a single, fused body segment and do not produce silk or build webs, often found outdoors in damp environments. In contrast, Cellar Spiders are true spiders, characterized by two distinct body segments and the ability to spin messy, irregular webs, typically in indoor spaces. Their differing survival capabilities make this distinction important.
Their Survival Without Food
Both Harvestmen and Cellar Spiders can endure periods without food, though the exact duration varies. Larger spider species, such as tarantulas, can live for up to two years without eating due to greater energy reserves and slower metabolism. Smaller house spiders typically survive for one to two months without food. While specific data for cellar spiders is limited, anecdotal evidence suggests they can survive over three months without prey. Harvestmen, though capable of long periods without food, are highly susceptible to dehydration, which significantly shortens their survival time.
Influences on Survival Duration
Several factors influence how long a “daddy long legs” can survive without food. Environmental conditions play a significant role; lower temperatures reduce an arachnid’s metabolic rate, extending survival time, while higher temperatures increase it. Humidity is another external factor; higher levels prevent desiccation, important for survival, particularly for Harvestmen. Internal factors also contribute, including age, overall health, and activity level. The size and nutritional content of its last meal directly impact its energy reserves, with larger lipid stores allowing for longer starvation periods.
Physiological Adaptations for Endurance
These arachnids possess specific biological mechanisms to withstand periods of food scarcity. A primary adaptation is their low metabolic rate, allowing efficient energy conservation. Spiders can further reduce their metabolic rate when food is scarce, sometimes by as much as 50%. They store energy primarily as lipids (fats) and glycogen, crucial reserves during starvation, with lipids being particularly effective for long-term storage. Furthermore, their exoskeletons help minimize water loss, essential for survival when food is unavailable. Some species can also obtain water through ambient humidity or from their prey.