Q.67 Dung beetles, live in regions where cattle graze, quickly burying and recycling cattle droppings. Because of the dung
beetle’s activities, breeding habitats for disease carrying flies are reduced, and the plants upon which cattle feed are
nourished. The relationship between the dung beetle’s, and disease carrying flies is a type of –
1. mutualism
2. commensalism
3. intraspecific competition.
4. interspecific competition.
Dung Beetle vs Disease Flies: Interspecific Competition
Dung beetles provide ecosystem services by recycling cattle manure, reducing parasite habitats. This MCQ tests species interaction classification—key for ecology sections in competitive exams.
Correct Answer: Option 4 – Interspecific Competition
Dung beetles and flies compete for the same resource (cattle dung). Beetles bury dung rapidly, denying flies breeding sites. Dung beetles benefit (+); flies harmed (-). This is interspecific competition between different species vying for limited dung pads.
Explanation of All Options
Option 1: Mutualism (INCORRECT)
Both species benefit (++). Example: Bees pollinate flowers. Here, flies lose breeding ground—no benefit.
Option 2: Commensalism (INCORRECT)
One benefits, other unaffected (+0). Example: Barnacles on whales. Flies suffer reduced reproduction—not neutral.
Option 3: Intraspecific Competition (INCORRECT)
Same species compete. Example: Deer fighting for grass. Beetles (Coleoptera) vs flies (Diptera) are different species.
Option 4: Interspecific Competition (CORRECT)
Different species compete for shared resource. Beetles win dung access; flies lose habitat. Classic exploitative competition.
Species Interaction Summary Table
| Interaction | Effect on Species 1 | Effect on Species 2 | Dung Beetle Example |
|---|---|---|---|
| Mutualism | + | + | N/A |
| Commensalism | + | 0 | N/A |
| Competition | – | – | Flies harmed by dung burial |
| Predation | + | – | Dung beetles eat fly larvae? (not primary) |
Ecological Benefits and Exam Relevance
-
Benefits: Reduces fly vectors (e.g., bush flies), recycles nutrients, improves pasture.
-
NEET Link: Organisms & Populations chapter; distinguish intra/inter-specific.
-
Trap Avoided: “Reduced flies = symbiosis?” No—harm to one = competition.
Mnemonic: “Different dung-dwellers = Interspecific interference.”
