Briefing Document: Personality Traits in the Tiger Mosquito, Aedes albopictus
Source: Cordeschi, G., Mastrantonio, V., De Nicola, C.
et al. Insect vectors have personality: first evidence with the tiger mosquito
Aedes albopictus.
Sci Rep 15, 39943 (2025).
https://doi.org/10.1038/s41598-025-23665-wDate: Received - 16 June 2025 | Accepted - 08 October 2025 | Published - 14 November 2025
Executive Summary
This document synthesizes findings from a foundational study providing the first evidence of animal personality in a mosquito species, the tiger mosquito Aedes albopictus. Researchers investigated personality traits in the larval stage, a critical phase in the mosquito life cycle. The study demonstrates that individual mosquito larvae exhibit consistent, repeatable differences in behavior across time, specifically in the traits of activity, exploration, and boldness.
Key findings indicate that these traits are not only stable within individuals but are also significantly correlated, forming a "behavioral syndrome" where more active larvae are also bolder and more exploratory. These individual behavioral variations were observed independent of sex. The discovery of personality in mosquito larvae challenges the traditional view of insects as having purely stereotyped behaviors and introduces a new dimension of intra-specific diversity.
The implications of these findings are substantial, impacting both basic mosquito biology and applied public health strategies. Larval personality may influence population dynamics through differential resource acquisition and survival rates. Furthermore, these traits could persist through metamorphosis ("carry-over effects"), affecting adult mosquito characteristics such as dispersal and disease transmission potential. Critically, the study suggests that the effectiveness of current larval control methods—both chemical and biological—may be influenced by the personality composition of a mosquito population. This research lays the groundwork for incorporating behavioral ecology into vector control strategies and the management of mosquito-borne diseases.
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1. Introduction: The Concept of Animal Personality in Insects
Animal personality is defined as consistent, inter-individual variation in behavioral traits that is stable across time and different contexts. For the past two decades, this has been a central topic in behavioral ecology, primarily focusing on vertebrates. Key personality traits include boldness (risk-taking), exploration, activity, aggressiveness, and sociability. These traits are often correlated, forming what are known as behavioral syndromes.
A growing body of research demonstrates that personality significantly influences ecological and evolutionary processes by affecting:
- Population demography and persistence
- Local adaptation
- Dispersal dynamics
- Species interactions
While initial research concentrated on vertebrates, an increasing number of studies have documented personality in invertebrates, including insects. This has challenged the conventional view that insects exhibit purely stereotyped behaviors. It is now evident that personality shapes insect population ecology and evolution. For instance:
- In the field cricket Gryllus integer, populations exposed to higher predation exhibit reduced boldness.
- In the firebug Pyrrhocoris apterus, bolder and more exploratory individuals are more likely to disperse and host parasites.
Despite this progress, the existence and implications of personality traits in mosquito species remained an unexplored area of research until this study.
2. Study Context: The Tiger Mosquito (Aedes albopictus)
Mosquitoes (Diptera: Culicidae) comprise approximately 3,500 species and are globally significant vectors for major diseases affecting humans and animals, including malaria, dengue, yellow fever, and chikungunya. The larval stage is a critical part of their life cycle, as it is when they accumulate the necessary food reserves for metamorphosis. Conditions experienced during this stage can have lasting "carry-over effects" on adult traits and, consequently, on their potential to transmit pathogens.
The subject of this study, the tiger mosquito Aedes albopictus, is an invasive species native to Asia that has spread to every continent except Antarctica. Its rapid expansion and capacity to vector several arboviruses make it a major global threat to public health.
The primary objective of this research was to address the gap in mosquito biology by investigating the presence of personality traits in Ae. albopictus larvae. Specifically, the study aimed to:
- Characterize the larval personality traits of activity, exploration, and boldness.
- Assess whether these traits are consistent and repeatable over time.
- Determine if these traits are correlated, indicating a behavioral syndrome.
3. Methodology
The study was conducted under controlled laboratory conditions using 41 Ae. albopictus larvae (16 males, 18 females, 7 unsexed) sourced from a mass colony. Each larva was individually tested for three behavioral traits on two consecutive days.
Trait | Definition | Measurement Method
Activity | The general level of an individual's movement. | Percentage of time a larva spent performing "thrashing" behavior (energetic lateral body flexions) in its housing tray over a 10-minute period.
Exploration | An individual's reaction to a new situation. | The number of unique 2x2 cm cells crossed by a larva in a novel, larger arena over a 10-minute period.
Boldness | The propensity for risk-taking behaviors. | The latency (in seconds) for a larva to re-emerge at the water's surface after diving in response to a simulated aerial threat (a standardized shadow stimulus).
Statistical analysis was performed using Generalized Linear Mixed-Effect Models (GLMM) to assess the repeatability of each behavior, with individual identity included as a random factor and sex as a fixed effect. Spearman’s rank correlation was used to test for relationships among the traits.
4. Key Findings
The study produced three principal findings that collectively provide the first evidence for personality in a mosquito vector.
4.1. High Inter-Individual Behavioral Diversity
The larvae displayed a wide range of behaviors across all three measured traits, demonstrating significant diversity among individuals.
- Activity (Thrashing Time): Ranged from 5.2% to 92.6% in the first trial.
- Exploration (Cells Crossed): Ranged from 12 to 111 cells in the first trial.
- Boldness (Re-emergence Latency): Ranged from 24.63s to 370.02s in the first trial.
4.2. Behaviors are Repeatable and Consistent
All three behavioral traits showed significant repeatability across the two trials, confirming that the observed inter-individual differences were stable over time. This consistency is the defining characteristic of animal personality. Sex was found to have no significant effect on any of the measured traits.
Table 1: Repeatability Estimates for Behavioral Traits
Trait | Repeatability (R) | 95% Confidence Interval | P-value
Activity | 0.415 | 0.116–0.664 | 0.007
Exploration | 0.354 | 0–0.567 | 0.019
Boldness | 0.448 | 0.104–0.701 | 0.011
Significant traits (P ≤ 0.05) are shown in bold. | | |
4.3. Evidence of a Behavioral Syndrome
The study found significant correlations between the personality traits, indicating the presence of a behavioral syndrome. More active larvae were also found to be more exploratory and bolder.
Table 2: Correlation Matrix for Behavioral Traits
| Activity (Thrashing) | Exploration (Cells Crossed)
Exploration (Cells Crossed) | 0.44 (p=0.003) | -
Boldness (Latency to re-emerge) | 0.12 | -0.35 (p=0.027)
Significant correlations (P < 0.05) are shown in bold. A negative correlation with latency to re-emerge indicates that more exploratory individuals were bolder (i.e., re-emerged faster). | |
5. Discussion and Implications
The discovery of personality in mosquito larvae has wide-ranging implications for ecology, evolution, and public health.
5.1. Ecological and Evolutionary Consequences
- Resource Exploitation: Variation in larval personality can lead to different strategies for resource exploitation. More active and exploratory individuals may encounter more food, leading to faster growth, while bolder individuals may gain greater resource access at the cost of higher predation risk.
- Carry-Over Effects to Adulthood: Personality traits established in the larval stage could persist through metamorphosis into adulthood, a phenomenon observed in other insects. This could influence critical adult traits such as:
- Fecundity: Larval nutrition is known to affect adult female fertility and size.
- Dispersal: Bolder individuals often show a greater tendency to disperse.
- Vectorial Capacity: Traits like biting rate and pathogen susceptibility can be influenced by conditions during larval development.
5.2. Implications for Vector Control
The presence of larval personality may significantly affect the success of mosquito control strategies, which often target the larval stage.
- Chemical Control: Personality could influence insecticide exposure. For example, a study on maize weevils showed that more active individuals were better at surviving insecticide pressure by moving to untreated areas. Similarly, bolder or more active mosquito larvae might have different exposure profiles.
- Biological Control: The effectiveness of predators used in biological control could depend on the personality of the prey. Predictable, consistent behaviors in prey can be exploited by predators, while a diversity of behaviors within a population could reduce predator efficiency.
5.3. Study Limitations and Future Directions
The authors acknowledge a limitation in the experimental design: the genetic background of the larvae (whether from single or multiple mothers) was not controlled, which could influence the interpretation of repeatability.
Based on these foundational results, the study proposes several avenues for future research:
- Field Studies: Extend the research to natural populations to understand the frequency and ecological relevance of these behavioral types in the wild.
- Genetic vs. Environmental Factors: Investigate the relative contributions of genetics and environmental conditions in shaping mosquito personality.
- Ontogenetic Consistency: Explicitly test whether personality traits observed in larvae persist into the adult stage and how they affect adult fitness and vectorial capacity.
6. Conclusion
This study provides the first empirical evidence of personality traits and behavioral syndromes in mosquito larvae. By demonstrating that individual Aedes albopictus larvae exhibit consistent differences in activity, exploration, and boldness, the research adds a new dimension of intra-specific diversity to our understanding of mosquito biology. These findings open up new avenues of inquiry into mosquito ecology and evolution and have critical potential implications for the development of more effective and nuanced strategies for controlling vector-borne diseases.